Re: Age related deceases.
What sort of diseases?
Are these something that would disqualify them on an medical exam but you're worried something might happen before they take their next one, or something else?
A lot depends on the character of the person you are trying to reach.
Edit: keep in mind that unless the impairment caused by the disease(s) is blatantly obvious, your friendly advice may be taken by the person as amateur advice; not something they will follow up on.
You might probe to see if they are getting concerned at all about their own abilities. Might provide a way to concur and convince them to followup with a doctor and/or CFI.
