Crosswind Limits/Lembrado,
If he has enough money to buy a Citation and he has enough money to do the endorsement, then whether or not he does it privately for his own amusement or whatever, is of no concern to anyone other than him. How he spends his money is none of your business. How he earns his money is also none of your business.
All he asked was for some advice.
Either give it graciously or don't give it at all.