I have two sons and if I tried tying either one to a tree when they were teenagers, I’d be the one tied to the damn tree.
OP, regardless of the jacket you pick, make sure you set the example and wear the same one.
As far as the auto-inflates go, yes there is a small failure rate. However the rate is extremely small compared to the rate of people that won’t wear a regular pfd because they’re too hot, too bulky, too restrictive, etc.
I wear an auto-inflate 100% of the time I’m fishing alone in my boat. I wore a regular pfd 0% of the time while fishing previously.