Client has dementia..? Keep working for her?

So the client I work for she is amazing in a million ways.. she’s such a go getter dreamer etc.. and now best selling author of a best selling book... but here’s the thing.. she has dementia..like I don’t mean it in a joking way - I know is a serious subject.. my own grandmother passed away for Alz.. and to be honest I am not a doctor,. But this client I work with.. she sometimes sincerely doesn’t know up from down, she can’t read her schedule updates, she forgets which day is what, forgets things she said the day before that were on a totally different track now she wants to go the opposite direction with the work we do.. it’s getting really confusing and often seems like we back peddle. She pays really well but i always have this feeling she’s going to flip out and fire us at any week because she talks about stopping services then the next day says she has a whole years worth of work for us with examples of the work ideas and everything .. she takes up 75% of my time, and I find myself very short on time to look for other clients and then find myself worrying about getting fired.. getting confused myself about the work ahead of us.. we are talking like 10s of thousands of dollars in work.. at such a loss as to what to do... just a hard situation.. any ideas ? And crazy client stories you could share ? Do you just what.. find a bigger client and say you don’t gave the bandwidth for her work? Or find a way to separate yourself or stop worrying ?