This. My father has been living with me, my partner, and my son since last year, following my mother's death. It's a similar situation to the one described here, where he helped with the downpayment and we pay the mortgage, taxes, and bills.

And, sure, there was some friction and growing pains as we all (re-)learned to live with each other. But it's been fine and good, and it lets me support him in a way I couldn't otherwise. It's definitely a different dynamic to if we lived in separate places, but it's not a bad dynamic at all.