Holy crap you can drive entire semis through the holes in this story...

My soap opera brain thinks money may be involved somewhere, perhaps an inheritance, or a legal or insurance settlement; anything to do with beneficiaries. It doesn't have to be on the son's side either, it could be on the new wife's side.

Either way, it doesn't change the fact that LW's son is the father of his twins in every way that matters. The twins are completely innocent here, and their needs must come first. (Especially if the son's previous wife is no longer in the picture.)