My Jr. High music teacher died from brain cancer. He was brilliant, highly-skilled, and excellent with showing kids their vocal potential. He remembered everyone; name, rank, serial. And he never gave up on any of them.
One of the more painful memories I have, ever, is of meeting this man a few years later, at work: He's browsing movies, and I'm coming back from a long day of installing satellite dishes -- my first "real" job.
I'm all "Mr. [ZZZ], how are you? I haven't seen you in awhile."
And he's all "Uh, hi. Yes! Yes, I remember you! You're uhm, Jason? No that's not it. Andy? No no. I'm very sorry, but they tell me I've got brain cancer and it's really hard to remember..."
Me: "Can I help?"
"No, no, they say I've still got 72% of my brain left. I've got brain cancer, haven't you heard? Let's see, uh, I know I know you and I'm very embarrassed that I can't name you."
At this point, I let the then-old-to-me damaged dude (45-50-ish) know my name, which still drew a blank. It was difficult excusing myself from that situation, and apparent that the missing 28% was inclusive of all of his genuinely-beloved students. He died a year or two later. Mein herz brennt -- I used to could talk to the guy about anything.
I mean, FFS: My grand-dad died from Parkinson's, which is a terrible fucking way to die when it gets stretched to multiple years of uselessness: You still know everything, but you can't do anything about it. (He was an engineer, but couldn't communicate his ideas at all. One scribbled note, discarded by the nurses because they'd since moved/re-adjusted him and no longer cared, said "Neck hurts." By the time I got there, they didn't care about my interpretation. He cried, which was perhaps the best he could do, paralyzed and unable to speak but having successfully had his written complaint understood only to be ultimately ignored).
My other grand-dad died from a bad stroke, leading to other strokes. This is also a terrible fucking way to die, especially it also involves years of uselessness. (He was a salesman and a wildly successful realtor and a lot of other first-party things, but couldn't reach the people he used to know after the first real stroke)
Fuck all brain diseases, in general. But brain cancer? Sheesh Fuck that one in particular. Brain cancer is silly-crazy-scary. Shell-of-a-ghost-of-a-human scary. I wish we could fix that one. At least my grand-dads knew who I was.
(I'd tell you about the staph infection my school-teacher aunt got in her own brain, but she's mostly better, ish: She used to know everything, and she's sure that she still does, but she's a bit more reserved about relaying that than she used to be.)