Beatnik 2: Meet The Knowing enemy
The interesting thing about my speculation as to Elly's past is of course that not only do her children and the children of other people suffer because of her one-sided rivalry with a woman who barely knew her when she went away when they were in regular contact back in the 60s is that it seems also likely that they suffer because because Elly never reacted well to the presence of having a kid brother.
This is because it's kind of obvious looking at the strip that Elly can't hold more than one concept in her head at a time. As such, it seems likely that she can never believe that her parents can love two people at the same at the same time. Thus the non-stop bitterness because she has a kid brother who she is certain is meant to supplant her. Phil is aware of this and always seems on the verge of telling her that she's full of hot gas about being mistreated.