I lost my grandmother to breast cancer that metastasised to her brain when I was 12, she was essentially my only mother figure. She had severe dementia symptoms at the end which is how we found out she had cancer at all.
It was not an easy thing to go through, I still remember her being so afraid all the time because she couldn't remember my grandfather and didn't know why he was in her house. She struggled to drive and ended up crying and demanding I take her to the store because we were home alone together (before anyone knew what was wrong) so I got a crash course in driving that thankfully didnt end in a crash. She remembered my sister and me until the end but struggled with almost everything else. I still struggle with guilt and shame of being so helpless and powerless to do anything to help her.