You might have just clicked on the child sim too early for the interaction to show up but all 'Hates Children' sims I've played can help kids with homework. They do get whims to be mean to a child and will get tense if they 'try for baby' but generally when directed can be just as nice to a child as any other sim. Left on their own they do tend to smash doll houses and do mean interactions with non-household children and sometimes to the kids in the household as well.