Why bring the daughter or your view of her into it at all? It’s irrelevant to Felling and his character or lack thereof.30 or so years ago, that would’ve been cringeworthy. But Marty’s in his mid-50s now. I fail to see any issue with a mid-50s woman marrying an older man. It’s not like she’s a teenager.
That said, I have no idea about Ron Felling’s life or lifestyle. If he’s in a bad way, that’s a shame. But if he did in fact marry somebody his daughter’s age, they’re both well past the age where that would be problematic.