The problem I have with this arrangement is not just that we're dealing with Lynn using her characters as a means of blathering away about how certain jobs are just for men or her fear that people will be as ready to cheat on her because they got bored as she was. The problem that I have is that it seems as unsustainable in print as it was in her real life. First off, let's remind ourselves of the fact that Mike is more like a very lousy and distracted sitter than he is any sort of father. Lynn might harrumph about what a great dad he is because he does what a good father does and bring in lots of money and that's all he's supposed to do but, well, having an overworked mother and a tetchy ghost who seems to have internalized Elly's need to shoo him away because agreeing with her on that finally gets him the approval he craves for parents is really going to do a number on Meredith and Robin. It's sort of obvious that at some point, they'll learn to stop bothering him and, eventually, stop resenting him. He'll think that they're close but the one who moves away will just be someone being kind to a stranger they used to know once.
The one who stays, of course, will be taking care of someone who's functionally an invalid because not only will he have forgotten any sort of life skills, he'll also be wondering why the Hell his marriage collapsed just because he put off his own retirement plans because crazy people wanted to take creative control away from him. He gave Deanna his name, he gave her a sewing school and he gave her fame so wanting to feel like a person instead of an appendage to a flawed creator isn't going to compute. Eventually, he'll make stupid noise about how he did it all himself despite the fact that his epitaph should be "You didn't build that."