What can I do when my mother in law wants me to sit in her room for hours, forgets things and gets angry saying we "never tell her anything

jeannegibbs, thank you for your ideas. I will try that. What would you do when she brings up things that are in the recent past... 2 years...and gets angry and says that "no one told me that! Everyone tries to keep me in the dark!!" and I have to spend another hour reminding her of the thing that she has forgotten. I'm worn out. And about once a month she will ask why she has to take all her meds... I have to spend another hour explaining each pill to her. her doctor told her and me that I need to have the meds and dispense them but she won't let me.. she throws a fit. I need to learn to go ahead and DO these things without feeling guilty or upset about it. How do I do that?