he can request leave, but it's up to his unit commander if he can take it, and there's lots of factors. good luck.
Nope. Not unless you are married and you died and even then it is iffy, why would you want to?
Nope, doesn't work like that. The only way something like that would work is if you're a close family member with a real, verifiable emergency that required their presence. Even that would have to go through the Red Cross.
Also, watch out for the military posers... way to many of them around.