Everyone should have CPR/First Aid training. Doesn't mean to have to use it - just in case.
There probably wasn't anything you can do - he was being cared for. At least it mattered to you. That's enough. If something happened just know he was doing what he wanted. Also just know sometimes it's foolish to do what you want (like riding in heat!). If you are out riding alone, do you wear a Road ID? You should. If you are going out always make sure you let someone know - I tend to email friends what I am doing and I check in later.
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Private docent led mountain bike rides through Limestone Canyon. Go to
letsgooutside.org and register today! Also available: hikes, equestrian rides and family events as well as trail maintenance and science study.