Ask HN: My Cofounder is on OPT

My cofounder for my startup is on and OPT F-1 visa. I was wondering what the best trajectory would be to a more permanent visa. Unfortunately they are Chinese which makes the whole process more difficult. Has anyone dealt with this before? Any practical advice? We are obviously working with a lawyer, however it would be helpful to know what questions to ask, rather than simply going in blind.