Struggles

Amber
So....his birthday is Saturday, he promised two months ago he'd take home time and be here. I planned a thing....talked his parents into coming down. (They live in Chicago, we live in NC, they rarely travel because of health issues) got his brothers to come down, because he's been talking about how he would love to get his family together. 
Today, he says he's probably not coming home, has the opportunity to get a bonus if he stays out another month. We don't need the money, financially we're comfortable, have a decent savings account...etc. 
I'm not sure if I can really even be upset since it's his birthday and he should spend it how he wants. I think I'm more bothered by the fact that he's going to be gone another month....he's been out a little over 4 weeks now. At first, it was because he's got a trainee, which was fine, no big deal,  but he sent him out on his own a few days ago...now it's this bonus...and a broken promise. Not even sure how to approach this with him.