Is it acceptable for an employer to make a soldier work extra hours during the week to make up hours missed for drills?

So I reread my post. I left some stuff out. I apologize. He has had other issues with this employer, scheduling him on drill weekends, working him till 3-4 am the morning of a drill or order date. When he has drill or orders the shop he works at will max out his hours allowed by the company. When he does not have drill or orders his hours are not maxed out. I have seen his time sheets and it's pretty consistantly exactly as stated above for the past year.

Well if they make him work when he available then he need to tell them he not available if he don’t wanna work. Also since he is hourly then the money won’t hurt cause he is getting paid for his time. What kind of work he do?

I'm not sure if they are allowed to do that, but when I was in the guard I would volunteer to work longer hours the week leading up to when Id be gone. Yes they have to let you go by law but its an inconvenience to them, and if you aren't willing to work with them they will remember that come time for promotions. Its illegal to discriminate based on military status, but its not illegal to use his willingness or lack there of to help the company out when it comes to weighing raises and promotions.

Sorry I meant 3-4 hours longer per day.