Hello sunbeem: I'm sorry you are struggling. My father had Parkinson's. As far as I am aware, it's not inherited. So I presume there's no reason to think I will get it. I'm already in my late 60's.
I would imagine that depression can be a big problem for people who have this disease. I'm not aware of anything in particular as far as remedies for Parkinson's-related depression. In looking over a few Parkinson's-related websites that discuss depression, it appears the same things that can help with other types of depression are recommended for a person who has Parkinson's. I assume you're in touch with the National Parkinson Foundation:
Understanding Parkinson's | National Parkinson Foundation
Have you looked into support groups in your area? Having the opportunity to share with others might be helpful. If you are physically able at the present time, doing some volunteer work might also help you to have a more positive outlook.
I'm sorry I don't have better suggestions for you. Perhaps there will be other members here on PC who will have better suggestions. Are you a member of NeuroTalk... PsychCentral's sister website?
NeuroTalk Support Groups