I don't think shelf life has much to do with what works and what don't.
The strength to load a magazine, work the slide, clear an obstruction, the ability to idenity a threat, accessability, and willingness, are players in the decisions to be made.
Apparently he is up to it emotionally. Only you and he can resolve any other physical or occupational stumbling bumps in the road.
If you two go out for a shooting outing, please, try not to preach or 'talk down' to the student. That is a slippery slope and can well turn counter-productive.