MooreBonds
Thinks s/he gets paid by the post
I've been thinking you could also turn it around and ask your future SIL if he has any advice for you, considering he is in an MBA program and you are nearing retirement. He might love talking about finance in general, megabusiness trends, interest rates, etc., and funding retirement and other big purchases in particular. No need to talk specific dollars, just percentages, and your DD might be happy to see you respect his opinion and hard work in the MBA program even if his area isn't directly related to personal finance.
Give them a gift subscription to Money magazine for Christmas.
I really like both of these ideas! (Well, perhaps if I had to pick 1 magazine, might lean more towards Kiplinger's rather than Money). Especially the MBA-experience thing. But just remember that many MBA programs never touch on personal finance, and he many not know anything. You could perhaps start off by asking about his job and things he uses in his job from his MBA background, and then some time later hit up your personal angle of the "any advice on people nearing retirement" bit.