If I do an affidavit, will i be responsible for him only financially, or will it include his new US citizen wife &children?

Although this is a complex issue, the short answer is that a co-sponsor is only liable for the "immigrant", i.e. your cousin.

Does my cousin have any chance of requesting derivative citizenship if she can prove my uncle was a US Citizen citizen?

Only Ted Cruz can be a derivative citizen. Seriously, based on the information provided it is doubtful your cousin is a US Citizen. Then again we...

You really need to visit with a Board Certified Immigration attorney about what is actually a very complicated case. Also, you should visit with a...

Can I get a working visa after my student has visa expired and with the resident visa in process?

I assume you mean you had F-1 status which you let expire. The "resident visa" you refer to will take much longer than you think and since you are...

G-325A full time student

You must list all employment on that form. I more important question is what are you filing the G-325 for?

Am I eligible for EB2 classification for my PERM application if I had 8 years of total experience in the same field?

This is entirely too complicated to address in a blog. You really need to visit with a Board Certified immigration attorney. Yes, you can use...

Adjustment of Status

You can adjust status if you can prove you have properly maintained your immigration status at all times since your very first entry and prove that...

Can I adopt my maiden name as my middle name during green card interview?

Married women use both their maiden names and married names together. They do not change their middle name without a court order or naturalization.

What are options to keep him here?

This is the kind of thing you really must discuss with a qualified, Board Certified Immigration Attorney. We do not have nearly enough information...

Will i be able to file for my brother and parents if i have green card?

You must be a US citizen to file for parents or a sibling. A permanent resident can only file for a spouse or child or a son or daughter (meaning...