It might be difficult to understand until your mother becomes completely irrational, wacko if you will. The irrationality degenerates into total inability to function and total intransigence and absolute single mindedness.
It is very sad and the ability to perform actions that might mitigate the situation just disappear into the air
Those who have watched a loved one succumb to Alzheimers until it kills them and nearly anyone who tries to take care of them will have a little better perspective on this. But it is still a very sad story. I know a woman who was a vibrant Lady in her younger years, and now she is so heavy that her bottom has become the shape of the leather recliner she dwells in. She can still get up and walk, but perish the day when she has a stroke or become unable to get out of the recliner. very sad and totally lacking in human dignity when that arrives.