Overtime and payroll entry laws?

OK, my brother is working for an establishment he has been at for 3 yrs. He is hourly. His boss is salaried. He worked 7 hrs. of overtime in one week. Instead of sending that through on payroll, his boss removed 4 hrs. of that OT, and told him she'd put it on the next week. That is ILLEGAL! So, my theory is...she is salaried, but she isn't working the 50 hrs. they require her to work, she barely works 30 hrs. She sees him getting 7 hrs OT and freaks because not only will it drive up her labor cost, but it will make her look bad because she should be using herself to cover those hrs since she is salaried. So in essence, she is hiding his OT to save her labor, cover the fact that she works less than 50 hrs and that she is covering the fact she is unwilling to cover hrs with her salaried position when she could save the time by working these shifts herself. Does that make sense? So, what can be done? You cannot move hrs in a workweek! ILLEGAL! Can't they be fined?