Have no idea what his mother died from.
Could be she had cancer or died of some other natural cause. But we don't seem to know at this point.
What if it was accidental overdose, or self-inflicted or some harm was done to her? Might, and I say might, give us some insight into this case. In addition to other possible insights...Karr himself claims she raised him like a girl. Hmmmmm.
I'm not saying it was from any of those causes...I don't know.
I do know that a lot of times in a story it will be included WHAT the person who died "out of phase", so to speak, died from.
Makes me wonder, that's all, if there's something there of significance that hasn't been told.