J1 important docs and visa question urgent

[samv18]

My friend got J1 visa which is for only 45 days(visa stamped on passport). I dont know how much he will get at port of entry. My question is if he get more than 45 days visa at port of entry, can he stay more?

What are the important documents do he need to carry with him if I he is travelling?
Can he change hisstatus to F1?

Its very urgent.

Thanks

[kabkaba]

Authorized stay will depend on his DS form sent by the school/employer.
J1 may not change status because they are required to stay in home country for 2 years before they can enter again.

[samv18]

His employer told that he can change to H2B visa.. I dont trust him........Is it possible? and can he transfer from H2B to F1?