Hi I am working in usa on h1b visa and my labour and i140 is cleared, my elder son is stuiding in college his date of birth is June 28th 1991 , I am waiting for priority date to file i485, does my son needs to file for f1 and when he needs to do this and what is prosedure ,does he needs to go india for stamping f1 visa. Thanks

If your son is currently in US with H-4 visa, he can go to college. No need to change to F-1 unless he is going to grad school and wants to get OPT.