I disagree as far as the law is concerned. There is a huge legal difference between giving someone something of value while suggesting a gift in return, as compared to conveying something of value in exchange for a promise from the recipient to pay cash for it. In the former case, the donor is SOL if the recipient chooses to pay nothing. In the latter case, there is an enforceable contract (one that violates program rules). As a practical matter, the airlines will have no idea what the uncle and nephew might have said to each other.

I also wonder about these millions of miles from an uncle who is too old to travel. I'd quickly check these balances and make sure there is current activity to prevent expiration.