I filed I 130 for my sibling who is currently here in F1 status and doing PHD. I just got a letter from USCIS saying that the petition is approved however I have to wait for NVC for further process. My question is can he go ahead and file I 485 adjustment of status? and does anyone know how long will the rest of the process take. I have heard 10/11 years and I have heard not that much since he is already here. I would really appreciate it, Thanks in advance.