My boyfriend is passed out drunk in the car.

So I came home from work tonight to find my boyfriend passed out in his car with the window down. I tried to wake him up and I couldn’t he was scaring the sh*t out of me. I didn’t know what was wrong. I had just seen him at my work like 2 hours ago and he was fine. Finally he half woke up and mumbled I’m fu*ked up. I asked him if he could get out and come lay down but he said no and then he stopped responding to me. I waited by his car door for like 30 minutes before going inside. He’s okay he’s just really drunk and I don’t know what to do. He doesn’t need a doctor or anything like that he’s breathing fine. Should I leave him in the car? Should I wait in the car with him until he wakes up?