tldr; author is angry for getting banned from a few subreddits, mostly for "replying in kind" to things people said that offended him. He equates moderator power to that of cops that "throw flash grenades into cribs" and kill with impunity, but ultimately muses that moderators are more powerful than cops because they lack administrative hassles. Based on the language in his post-- I don't blame the moderators for banning him.
Don't feel guilty about this, or as if you and your brothers should have done something differently. It wasn't your choice to make-- it was hers and your parents'. They may have understood her condition and wishes differently, and had conversations you weren't a part of. In the moment, you guys didn't challenge the hard decisions your parents were making, and instead showed support. Which is doing something in its own right. Moreover, morphine can give a pleasant high, and combined with patient's own adrenaline surge around the times they're the sickest-- can make very sick people look much better. Consciousness/lucidity waxes and wanes a lot in sick people.
Your conspiracy theory approach to science backed by Youtube videos is obnoxious. The cause of Alzheimer's is still unknown, but most likely related to amyloid plaques. Diet may contribute. Or it may not. In a 38 year old, it's genetics. Period.
Meds aren't always so black and white. A treatment or drug may be successful in 70% of patients (or even 10%), and still properly prescribed when the potential harms outweigh the benefit.
What was the situation here, exactly? You describe a situation of being thirsty and a doctor calling to you get you water. Then you got the water and presumably your thirst was satiated. Healthcare is provided by entire teams of people, not just by doctors. Doctors are part of the service, but they rely on a team for a great many things.