The reason that I mention this is that every so often, learning impaired Mike ran into Lizzie's fist when his being a malicious clodhopper who thought that she wasn't allowed to be happy because his band of scruffy vermin would tease him if he behaved like a human being instead of an inflamed boil. What always happened went something like this:
1) Mike says something stupid and demeaning when a decent human being would shut his yap.
2) Liz gut-punches him.
3) He thought-bubbles that 'weaker sex' doesn't apply to his sister.
4) He promptly forgets this because learning things is a humiliation he cannot survive.
5) Goto 1. Repeat forever.
Since he's got a baked potato where a brain's supposed to go, he's probably wondering why his kids don't get along; after all, he's doing right by Eatdirt and telling him that women are objects so what could be wrong?