My father in law is very generous and treats us to travel, meals, golf, movies,
whatever. He insists on footing the bill and on those rare occasions when I successfully treat him to something it almost hurts his feelings. So for the most part I let him be the patriarch and thank him sincerely and appreciate the time we get to spend together.
With some people there may be strings attached or subtle pressures or expectations. But in my father in law's case, he was orphaned at 12 and I think it just gives him a huge sense of fulfillment to provide support and opportunities to his family in ways that weren't available to him as a youth, a young parent, or even a middle-aged adult. It means everything to him to be involved in each other's lives. I just hope we never take his generosity for granted in any way.