What Causes Fainting While Drinking?

My guy has been drinking. All of a sudden he slumped to the floor. I eased him to the floor. His eyes were glassy & he acted like he could here me but didn't answer. I lowered him to the floor and put pillows under his head. He now seems to be sleeping. His pulse is normal. Should I be concerned or has he drank too much and will come out of it. I've never dealt with this before. Our insurance is limited so didn't want to call an ambulance if it wasn't necessary. Breathing is normal.