I am not sure scace is the right word.
Strikes me that a lot of soon to be past use by date has gone over and looking at it from a very realpolitik perspective it is a very cheap way of degrading the Russian military, a lot of money but small beer is US military spending terms.
I have not heard of expedited biometrics bit they do not seem to take that long.
Being realistic I suppose relative to how long he has to go they will be back and firmly established in the US long before he is interviewed.
It is not anyone on here that has to be persuaded it is the Consulate.
Noted your Father just wants to visit.
Your Brother is looking at say a 30 year wait so if he goes that route he would be close to retirement presumably.
Of course not, I visited the US quite a few times, and knew nobody in the US, I did not need anyone to approve my visit.
They do not need your permission
Can she apply for a Visitor visa yes.
Will she get a visitor visa now that is another issue.
Does she need an invite, no.
DS 260 is the form she fills in when applying for a Immigrant visa
She fills in a DS 160 as part of the visitor visa application process.
Most companies use Lawyers, the big ones might have Lawyers in house.
The red flag arises where they do not have any internal resources and refuse to use a Lawyer.
I certainly can and did
https://dictionary.cambridge.org/dictionary/english/stepbrother
not your parents' son, but the son of a person that one of your parents has married
Do you share a parent?
Apart from anything else it is much quicker when the Parent files for a child than a sibling assuming you are blood related. If you do share a parent than you can also file. Good insurance.