You threw a test at him and now you're upset because he failed. He on the other hand thought you were doing it in good faith.
"if he cared he would have known"
This type of behavior will just lead to unneeded fighting and arguing. If you didn't specifically set a boundary then you have no one to blame but yourself. He's not a mind reader you know....
(I'm sure I projected a little there)
As for him staying out so late, so often. I definitely think its an issue. That needs to be CALMLY addressed. I used to be a server so I know how the crew hangs out after work. I did it too, although I never understood, how people didn't just want to go home after a long shift. I guess you need to come off the adrenaline. I also think its because most servers unless they also work lunch sleep in the day, and stay up at night, and since the industry works weekends and nights, the crew which is young to begin with feels like they have to make up lost party time.
Heres the rub, whether by choice or not, your boyfriend is now a family man. This means trying to accommodate more to a family schedule. He needs to accept responsibility and move forward, finish school, and be a provider.
You on the other hand need to keep it up with school, both for yourself and to inspire him forward. Who knows maybe you'll inspire him to finally buckle down with school. Get a great job, and stay in shape. If he is worthy to be with you he'll rise up to the challenge. If not at least you'll be independent.
It's hard and a fine line between holding on to your boundaries and nagging. Just be clear and non accusatory.