29?
I’ve seen bigger age gaps work out long term, but dang, not when the younger was still a kid in most ways. It comes down to there needing to be a certain degree of development of self before you can make a relationship be a meeting of equals where both people can move forward together rather than it being one leading the other (intentionally or not).
There’s really nothing you can do about it, though. Like you said, he’s a grown ass man and has to reap the crop he sows. If she’s legal there, and the parents aren’t objecting, there’s nothing that you can the that’s useful. You just hang back and see how it goes.
Treat it like you would if you didn’t like his choice in dating because she was stupid, or ugly. If he asks, don’t lie about your opinion, but don’t bother them with it either. Trying to force them apart is likely to backfire and at the very least could make them stick together longer than they otherwise would if it isn’t going to work out on its own.
People are allowed to make bad choices as adults. When it comes to family, there’s a limit to what kind and degree of interference is acceptable, no matter what the family member is doing.
You’ve had the unfortunate discovery that your son is likely an idiot about at least this matter. Could be worse.
I’ve called the cops before, when it went beyond the point of spanking (which is legal) and into abuse.
More than a few times. People don’t do it like they used to, but some people just don’t care. Last time, I saw a woman hit her kid in the head with an open hand slap. But it was loud enough that people came around corners wondering what it was, and the kid had been knocked down by it.
The very first time I ever called the cops about something like that, a dude was literally stomping on his kid’s hand. I was too young to realize I could have stepped in, but I sure as hell went to the pay phone outside the pizza place and called.