What to do w/ ultra-sensitive Senior Citizen who 1 minute feigns helplessness, then the next yells full volume?

Some of the symptoms you have described could be dementia or Alzheimer's. She needs to be tested by her doctor. Could be medication interaction. Is her thyroid functioning correctly? Most towns have Adult Day Care, if you have one take her there to give yourself a break. Count it as a blessing when she is pouting in her room. Go take a long bath, do something you want to do. She can get glad just as fast as she got mad. Put a TV in her room then she can watch what she wants. Don't ever feel guilty about what she says, she knows ALL your ons and will push them all at least once.