agrabs

I hate to burst your bubble but even after the interview,   the wait can be extensive
most residents of India go thru a long AP (administrative process) after the interview for the extra security checks 
 
 
 
What does USCIS expect me to do?! Stay in usa for 3 years and visit my husband once in a while until his green card comes through? 
they do the job that is expected of them / the choice is yours to go thru the system AS IT IS
 
i waited 6 years to bring my husband from first applying for k1 in 2009 to  2015 when he was approved and i am a born here in America USC

You must realize that there are, normally, over 1 MILLION I-130 petitions pending in the pipeline at any given time.   Most of us here have had to endure long distance relationships and the problems in the immigration system.  Bottom line is that the queue is long.  
You seem to think you are entitled to something........but there are many, many people in line already.  Good luck.

Sorry but your situation is hardly unique. USCIS is not concerned with long distance relationship hardships, this is a very formal, long and bureaucratic process. Virtually everyone on this forum is separated for long periods of time.
 
Yes.  Or meeting in a third country. That’s what most people are doing. 
 
With this argument, if US citizens are waiting 2-3 years to bring spouses, why would it be less for permanent residents?
 
It’s the last thing anyone wants to do.
 
Immigration takes a great deal of patience. It will test your limits but it is what it is. This is the reality.

So, you’re planning on lying on an official US immigration office application to get a TOURIST extension when your actual plan is to get married? Bad idea. Apart from the repercussions for immigration of misrepresentation, as others have pointed out, if the extension gets rejected (highly likely imo) you will start accusing unlawful presence and your tourist visa will be revoked,
 
is this person a US citizen or a green card holder, by the way?

Three times a month is still almost every week, which is a lot here in the USA unless they have some disease which needs very closely monitored.3 times a year would be much more normal for elderly people here, less for healthy adults. 
Even if you get health insurance for them, after a few months of this pattern, the insurance will look at them closely and may drop them (again, unless they have ailments which require weekly visits). Your best option may be a private concierge  doctor that they can  "subscribe" to with a yearly fee and unlimited visits, but that would be private, not covered by insurance.

As a warning, we have seen it here several times with elderly parents that the CO at the interview wants not just the I-864 proven, but also proof you, as the sponsor, can pay for their health care needs.

3 times a week? You should carefully reconsider.. ultimate decision is yours 

Nope.  He can file as married-filing separately, with only your name......He cannot legally file as single if he is married....period.

Assuming you are the Joint Sponsor for the child you can pull that I 864.

Have you tried to seek help in your country?  The US is not what some people think. 

* And they won't.  Because at this stage, it is irrelevant.  It only becomes relevant when it gets closer to the time for an interview.
 
 
A lawyer cannot impact the speed or outcome.  Some VJ members feel better using one, especially if they have a hard time understanding the complexities of the forms.
 
If she can get legal residence in another country, she could qualify to interview at the US consulate there.  However, an interview is YEARS away, since you are not even at the point to petition her.  Lots could change by then.  You're kind of jumping the gun.
 
I'd focus on her getting legal residence in a different country first, and then starting the petition process.

Asking for a friend.

At the interview stage the CO will also expect u to know the cost of health care insurance in your state and whether u can afford it
so check into this cost along with cost of any medications they may take regularly like for diabetes as insulin in now rather costly (just a sugestion)

I have no advice.  Just admiration for you, OP, for wanting to do what you think is best for you and your babies.  Bless you on this journey!
 
Also, I think your husband is a bit of a bum.

1. You are not a friend, but a fiance. 
2. When asked for purposes of trip at POE, she has to be truthful. Never lie. 
3. B1/ B2 visa is not for taking care of people. That is work, which visitor's visa does not permit. 
4. There's no 90 day rule. 
5. FYI, visiting with intent to adjust and stay is illegal. However, intent is determined at POE. However, preconceived intent is the Illegal part. 
 

It would be illegal to do this in your case because you are planning ahead to go against the purpose of the tourist visa, which is only for temporary visits and not for immigration. If she was already in the USA and circumstances genuinely changed (ex: her Canadian job suddenly laid her off while she was visiting you or something like that), then adjustment of status is allowed. 
 
Also when CBP asks her for the purpose of her visit with her B2 visa, she would have to be honest and say, "Well we're planning on me staying and then adjusting status." Immediate denial of entry and other possible consequences. Don't do it. If you want her to move here permanently, then file for the spousal visa. (Typed too fast. You guys are already married so you can file for spousal visa right away)

So, you are giving up on the planned marriage?  or do you another plan for marriage?  This plan doesn't make sense...unless you are planning to enter the US via a student visa, then marry and adjust status.  That is fraud.  

I doubt you  will get an F-1 visa before your K-1. 
 
If your future spouse is not able to support you financially, while you are pursuing your masters
degree, then get a spouse visa.
 
And yes you’ve expressed immigration intent and so unless the relationship with your petitioner is terminated I don’t see that it is likely the F-1 will be approved.  

Thank you everyone! That's great news, and a bit of worry off of our plate! We'll just be doing a simple courthouse ceremony first time around so hopefully it will all be quite straightforward then

Asking for help with illegal immigration is a term of service violation on VJ.   It's illegal to enter the US with a non-immigrant tourist visa with the intent to immigrate by AOS.  We can't help you plan this.  It's illegal.  

How are you planning to pay for health care?  Your parent will not qualify for Medicare or Medicaid.  

Letter can indicate u have a friend in the US with plans to marry here and adjust your status to stay 
it will not help your chances
 
u must apply with strong country ties to Mexico 
DO u own a home?
DO u have a good job to return to?
IS the friend a romantic friend ?
 
that is what embassy will look at
 
and ,  please,  if u do a letter of invitation and are successful ,  let us know so we can reference your post if others from Mexico ask this question
 
BTW a school teacher from Peru was denied 
her letter on invitation was from family here
she had a good job
she had to return to her job,  her policeman husband ,  her 2 kids
and they owned an apartment
and this woman and her husband had lived in Louisana while he attended university in the US and had left when college was over

You took the words out of my mouth (or my keyboard in this case).
It really begs the question as to why they chose AOS knowing that they are directors of a foreign firm and that they might to travel on a short notice.
If the possibility to work/ travel is a concern, then neither k1 nor AOS are the routes to take. CR1 it is.
OP now has three choices:
1.Apply for emergency parole (however, pretty much nothing is urgent for USCIS)
2. Continue to remain in the US and wait until AP is approved.
3. Leave now and start all over with a CR1 from the home country.

At this stage it is your petition and you can withdraw it without her being notified. Now if she has the file number she may be able to find information online about the status. If she doesn't have anything then don't worry about it. 
 
Do not petition anyone who is causing you anguish. Mother or not you do not owe her anything if this will be harmful to yourself. 

I've not seen one for grandparents.  Expedite for the father of the baby is much different.

Pregnancy and a visit for grandparents is not an emergency.