In MY experience,
The nighttime erratic breathing is scary, but probably just noisy. My AH makes all kinds of whacky noises, and his sleeptalking is truly bizarre--makes you really wonder what kind of demons he's possessed by at the moment. I never thought of calling an ambulance but I did consider an exorcist.
Even things that might seem serious aren't necessarily. Recently I was on a business trip and AH woke up next to our lawn mower. He thought he was having a heart attack because he felt a pain in his neck and he was sweating profusely. He called the ambulance for himself, and the diagnosis was exertion and alcohol--no heart attack, no stroke.
I called the ambulance once when he came back from a Robbie Burns night. I was going to leave him in the car because he had passed out, but my door opening woke him up, and he LITERALLY rolled out of the car and down the driveway into the street. I couldn't move him/pick him up. So I called the police who called an ambulance after I said he was drunk. He never went to the hospital. They just brought him in the house.
I would call the ER if he became unresponsive or if he were seriously injured from a fall.
But honestly, I don't think anyone can answer that question for you, except maybe a qualified medical professional. I agree with finding another place to sleep where you can't hear him so you don't drive yourself crazy thinking about it.