Documents for Medical Condition

[ararun]

Greetings, My company is processing GC for me and it is likely that I would get my GC mid next year. My Brother-In-Law is a special needs child. He is 41 years old and has a condition called Hair breath condition of cerebral palsy with mental retardation. In the USA it is a medical condition. I heard through my friends here that he can be brought in here to the US on the basis of treatment. Can someone kindly advice what are the documents I would need from India and also in the US in this scenario.

Thanks in Advance for your advice and help.