I like this very much, as my wife has always had a young(er) guy fetish.
I think this is a common ploy by young men who find themselves smitten by an older lady's charms. They all "want to be taught...".
And I know the first couple or so times, they are typically in a rush to penetrate and pound away until they cum.
And that's fine, perhaps even necessary, but the wife needs to take charge at that point.
Teach him the anatomy of a pussy, show him how to find and identify them, and what stimuli works best for each part.
The importance of foreplay and exercising the patience for maximum stimulation.
Different ways to penetrate, and, again, teaching to not be in a hurry every time.
How to move his cock around inside her, varying the speed of his strokes, attacking from different angles and demonstrating the differences.
Most of all, she should teach him how to properly eat pussy, as that may be the single biggest skill they need to master.
It's a lot to learn and they need to practice often!