hmm.. good thing it was frontal impact. Those bolt on roll bars can be disaster if you're hit from behind. The bar will move forward into the cockit.
Some have complained of back injury...
Accidents are one reason I stopped using the Miata as a daily driver.
With Porsches they say "buy the newest you can afford". In your situation I would say buy the newest safety technology you and he can afford.
As such, FRS for the win. Not too much power. Safe. Good feedback. Warranty. good price.
I can't think of another car that checks all these boxes to the same degree.
is he old enough to get a part time job to help pay for the cost?
and terrific customizing available at low cost (relative to Porsche/BMW/etc.)
Could be a good project car for the both of you.