I related to the beginning of this, because I recall that when my mum had cancer, one of the questions I asked her was something along the lines of "Where have you never travelled to that you wish you'd have been able to visit?" I think that was just reflective of what I thought I'd regret most if I knew I was going to die young the way she was (she was 50 when she passed away).

I'm glad my mum didn't have to take any drugs that completely upended her personality like this though. I think that would've been even harder for me to watch. In this case, I think I might've been like you, thinking it was brain damage, probably caused by the tumors, and freaking out over that. There's a part of me that still blames my mum's cancer on the fact she kept so much of her emotional trauma bottled up inside her instead of talking about it. I think in difficult times like this, our brains just try to grasp for whatever answers they can find to try and make sense of it all.

I hope things improve in your family, though.