What do I do? Please urgent!!!!?

So.... Yesterday I was unsure if my boyfriend was relapsing with his bulimia. Now I know he is because after dinner I heard him purge in the bathroom. Well we were on our way downstairs to the basement and right before we went down the stairs he stopped. I looked at him and he collapsed onto the floor. He woke up quickly and was so lathargic he couldn't get back up. Now he's drifting in and out of consciousness. My parents went out to the store, and his left him with us for the week for a business trip. I'm home alone and can't drive. Should I call for help or wait and see if he gets better?