Divorce and keeping GC

[livliv]

I am posting this for my friend.

She got married 3 years ago and traveled to the US with her husband on H4 Visa. (Husband on H1). Then her husband got his GC through EB1 and she got her GC as a derivative, about 2.5 years ago. However, things did not work for them and she left for India 2 months ago and decided to get divorced.

She is currently in India for the last 2 months and her GC is with her in-laws. She wants to come back on her GC and work in the US while the divorce proceedings continue and eventually keep her GC independently.

So she has the following questions.

Can she return to the US independently using her GC?

Does it matter where she gets her divorce? In India or in US? Her wedding was in India.

Can she get a duplicate GC while in India in case her in-laws do not give it to her?