How do you deal with a manipulative family member with a personality disorder?

A family remember has moved in with the grandparents and won’t leave. My grandparents simply won’t to kick her out – but she has been taking advantage (we suspect financially), confusing, and yelling at my grandmother constantly who has moderate dementia. She also refuses to help take care of them and frequently gets in the way of others helping. My grandfather is in hospital right now.

How do we deal with this abusive family member? Is there a way to kick her out of their place? (She has no diagnosed mental illness….but she has demonstrated over the years to be extremely sick in the head)