The girl is the winner here. That 63 year old man will likely be dead or bedridden by the time she is 25. He probably can't have kids.

The family money is passed on to her she gets a massive financial jumpstart when she starts her real life with someone else, likely a free house too. Hell, they might even get a divorce and cut it short in a few years and she keeps half.

It might look bad, but it seems like a fair trade. I'm sure the girl knows how to do math... She lets him take care of her and hit it for a couple years or however many months his libido actually works and then she gets a big payday out of it. Why does everyone always assume that young girls can't possibly have a brains? It's quite possible she smart enough to have thought this through. Would she be the first person who thought of marrying a much older man for financial benefits?

With that said, investigate the guy all you want if you think he's doing or has done stuff with minors, but the girl is an adult and can make her own choices. The dude is at the tail end of his life, so there's no much harm you can do to him. Throwing the girl out there as some sort of brainless brainwashed person who can't think for themselves does more harm to her than anyone.

Again, look into the guy all you want. But leave the girl out of it... She's probably just in it for the mill ticket.