I hope he realised you saved his life that day! Did he sell the aircraft after that?
Sadly, I don't know what happened, other than to say I'm certain that he flew the plane home solo, which I could not prevent, but very certainly did not endorse. I did quietly ask around his part of the country (a long way from mine), and nobody ever heard that that plane was involved in an accident, or incident. But I have no idea what happened to it. I hope he sold it to someone better suited to fly it.
There are all kinds of pilots, and some reach their personal glass ceiling of skill before others, or before some of us would expect. It's not worthy of criticism, other than to encourage skill limited pilots to choose to fly within their own skill sets. Sometimes that seems limiting for them, but that's just the way is is. Sadly, the middle aged "type A" personality, who has earned their way to being able to afford a fancy fast plane, is often one of the more difficult personality types to convince that they really "aren't there yet" in terms of flying it with the appropriate skill.