I don't know what to do! I appreciate any advice!

My mother is 74 and lives on her own. We have always been close, but over the last 4 months, there have been significant changes to her personality. She's been through a lot during these 4 months, but something else is going on, and I don't know what to do!

For context, in early March, a pipe burst in her home causing thousands of dollars worth of damage and she was diagnosed with an illness that's a step below narcolepsy. To combat the sleepiness my mother experiences, her Dr. put her on a high dose of Adderall. The stress of the home and this new medication really pushed her personality from kind and caring to controlling, vindictive, and non-stop guilt trips towards my brother and I. I try to be a "good son", but she's driving me away so fast it makes my head spin. All of the problems she creates for herself are the fault of my brother and I not doing enough for her (in her worldview). I'm so tired of being spoken down to and hearing her non-stop complaining about the bad situations she creates for herself. I'm also wondering if she's experiencing the first part of dementia, and this scares the hell out of me!

On top of all of this, she developed a lesion on her tongue, and the Dr. put her on steroids and she's been in pain for 2 months. She's having surgery to fix it in 2 weeks, but the steroids with the Adderall, the pain meds, and whatever is going on in her head has pushed me to the brink.

Has anyone experienced a sudden shift like this with an aging parent? There are so many things at play in this situation, and I don't know what to do! Thank you for reading!