designguy

Once the parent becomes a LPR they can file for the aged out child but it will take another 10 ish years

You need to calculate to see if CSPA applies. What is the Date of birth, priority date, and filing date of the peition, and approval date of the petition?

What is the primary beneficiaries visa category ? Have you calculated CSPA ?

Unless he is highly educated or has extraordinary abilities he will need a company in the US to sponsor him. If he wants to pursue the employment route. It will have nothing to do with you

What is your sister's household size? Did you send an I-134 from your cousin? Otherwise sending in his TT is meaningless And I think tomorrow is a holiday too

You can contact the consulate to ask if they can unnlock the DS-260 for you so you can update

Hmm ok they want to see that the sponsor is going to be financially secure so if his income fluctuates dramatically there is a chance that they will still say get a joint sponsor. Its just something to keep in mind. A salaried position at $55k is different than self employed making $55k when the year prior was $8k

Is there a problem if they do ask about it?

Is his new income through a permanent employed position or how did it change so dramatically?

google schengen visa

Sometimes yes you can ask to see an immigration judge. There is always a small risk that they straight up deny and don’t let you in. More likely is the RFE route. I forget exactly how many days you have to respond (I think something like 86) so you need to make sure you respond as quickly as possible and you should return around the same time. But unless you have some big red flag you should be fine

The only ones guaranteed entry are USC

I think the OP is really in a pickle here. As ban for IV from Nigeria is coming up, it will take a while to get a visa, if one is even granted with a waiver (probably on the more likely side considering its an infant). But on top of that if they dont get a visa for the son within the next 6 months the visas for the other family members will expire OP your wife may need to enter the US to activate her visa and return to Nigeria and hope that the son will get a visa quickly.

If they come on an F1 they must be entering grade 9 if they wish to attend a public school. You cant attend a public school for K-8 on an F1. Based on the age he might be right on the cusp

Health insurance can cost thousands of dollars per month per person depending on the age. If someone basically at retirement age this can weigh against them, in the sense that they could be seen as possibly becoming a public charge. No one here can tell you if its 10/90 50/50. The only certainty is that if you dont try, the chances are 0. You file a petition and then make a case to the IO and then based on the circumstances they will evaluate. Its also probably a year and a half till they would interview. A lot can change in that time. FYI for the siblings you are looking at 15-20 years ish