Two other suggestions:

Have you had your mother tested for Lyme Disease? It can be in her system for years before any symptoms show and there have been cases of secondary Parkinsonism depending on where the brain is affected. This could be a part of why she was misdiagnosed in the first place. It is a long shot, but your mom's behavior reminds me of what I have read about "Lyme Rage" where the affected person alternates between aggressive/violent behavior and hypersomnia. Sounds a bit like your mother's ups and downs. See this article with case studies.

Finally, you might want to call your local Catholic Social Services? Don't be put off by the religion; they help people in all walks of life. They have Social Workers who offer mental health services and programs for the aging; they might be able to offer some referrals right in you area.

Keep us posted!

Laura