Do we know that the mother supported her daughter’s psychoses?
She apparently eschews her daughter’s preferred pronouns. God knows that’s a trigger for some of them.
The fact that the mother doesn’t use the daughter’s male pronouns suggests that she didn’t support her transgender delusions. There are reports that the mother was Christian and worked at a religious school, so she may have held traditional views on gender. Would not suprise me if there were deep disagreement between that was a factor in the daughter’s actions. My impression is that her shooting up a Christian school was, at least in part, a viciously cruel way of inflicting some sort of punishment on her mother.