To explain why this is, we have to remember something he doesn't care to about Elizabeth. What we see, what we always see, is a frightened, passive little child desperately seeking to fit in and convinced that the world is passing her by and trying to leave her by herself, alone and unloved and vulnerable. It's rather sad to have to watch the poor thing look in the mirror and wonder why trading on her looks doesn't work any more and why she never seems to have the happiness and attention and love her cruel, ugly brother takes for granted. She spent most of her teenaged years alienated and lost because she was never allowed to have real friends because she had to fight Mom every step of the way to fit in with the others and be loved.
This means nothing at all to John because he's a dolt who wants a passive doll-child who fawns over him and doesn't complain about her lot in life because that's gross. Time and again, he had to be reminded that no, family wasn't enough and she wanted real friends who weren't obliged to love her and time and again he 'forgot' because it means that he and Elly should not be the only influences in their children's lives. He also forgot that Liz saught to recapture the early, happy days when Daddy loved her and never said to go away because she was in pain. This led to her ultimate ruination as a person. We call this calamity in which she defaulted on being a person in her own right as the dreaded Settlepocalypse.