I dont personally get why a man that old would want to date someone who looks like a child. I can see dating younger (30 or so) but not the age of your grandkids.
He's not "dating" them to sit on a porch, holding hands, reminiscing about growing up watching "Saved By The Bell" and riding their bikes down to the arcade with a pocket full of quarters.
The relationship is: Penis goes in. It's no deeper than that.