Xiaobaitu: a child want to enroll medical school/graduate school

Xiaobaitu; Please help!

My son is studying in U.S. university now using F1 visa during our I485s pending. He is considering to enroll medical/graduate school now. If he change F1 to AOS with AP and/or EAD, can he be treated as the same as GC holder for his medical/graduate school enrollment and financial application or still as international student?

When using AP re-entry U.S, usually how lomg will give on I-94 stamp?

Thanks very much for your time and help.