Of course age gap relationships can work.
I don't think anyone would deny that.
You are saying if he leaves in a couple of years, she will have had some happiness out of it. How does that when she realises, he was using her. How does that help her, when he divorces her, gets with someone younger and has kids? And she realises she's a means to an end?
That she could have spent these years, with someone who actually loved her. Yojr friends relationship isn't just about the age gap. Its about the RTR. I mean from a financial point if view, he would be best staying. Theres a good chance he can inherit before he is 50. The fact that he has negatively imoacted her relationship with her children, is awful.
You say its because they tap her for money. But its ok for her to support him? Perhaps the children are actually just seeing exactly what he is up to?
As in all relationships age gaps are complex. Anyone who consistently, dates only people alot older or alot younger, generally have issues. Thats both men and women.
People who have met and fallen for someone who happens to be older or younger, is a different situation.
Then there's where people are in their lives.
I wouldn't want either of my kids (a boy and a girl) to be with someone in their late 30s when they are 20.
Of course it can work. Any relationship can work. Age can just but one of those problems that people have to work with. We all have them in relationships.