U are hundred percent safe. If u were doing some job in Nepal,make a letter saying that this person was working here and we are happy do give him (unpaid leave)during his study in USA and will be happy to rejoin him once he returns from USA after completion of study.
I had a bank balance of 2 lakhs ready in my pocket (i did not show that) in case they talk abt it. But 3 of my friends (100% sure and dozens of  other with assistantship) made through the visa process without a single documnet.