boyfriend wants to enlist into the reserves!

Ja
My boyfriend is 16, about to turn 17. He has been talking with a recruiter for a couple weeks now about enlisting once he turns 17. The recruiter said yes, and gave him a bunch of paper work that him and his mom have to go over and fill out. I'm happy that he is doing something he's passionate about, but I'm terrified that once we graduate, and he's 18 that something will happen and he'll get sent out into combat. What am I supposed to do if he doesn't come home? He's all I have, and I don't want to lose him. I've tried to talk him out of it, but he has his heart and mind set on being in the Army. Any advice?