What a scare! So glad you son could help you! That's one smart boy. Just a thought... Does he know how to dial 9-1-1 and ask for help in an emergency? The next step in case patting on the back didn't help, or for other situations? I used to practice 9-1-1 situations with our kids as a "just in case."
We also did some of the family fire drill precautions about what to do if there was a fire and had an assigned meeting place for everyone to go, and the rule was get out and stay out...don't go back in. We also did the safety code word with our kids...they were never to go with anyone who might try to pick them up without prior arrangements unless the person knew the code word (we picked a word unlikely to be used or guessed, like "ostrich"). Later, in high school, the same word was a code for us in case they got into a situation they needed to get out of, but might not have the strength at the moment to stand up to peer pressure, such as refusing to ride home with someone who had been drinking. Or not really wanting to go somewhere or with someone, so when calling home to check in we could put our foot down and say, no, you need to come home now. If "ostrich" entered the conversation we knew they needed help of some kind and we'd drop whatever we were doing to come get them. I think maybe it was only used once, but it empowered our kids to know we'd help them if it was too tough to say "no" to their peers. It also clearly outlined our expectations for their behavior such situations. I said they should always, always blame us...we'd be the heavies. We were blessed and had very few major issues with our teens (but I'm still glad to be past the high school years...parenting teens is not easy!).