Father is an A**Hole. Completely.
Mother is use to being treated like a servant. Not loved. I hate my father.
Mother won't speak up. My father accused us of intimidating and scared of us. We are hardly home.
Grand kids are depleting their money. They are taking the fathers side and need suggestions how to handle this. Kids are financially abusing them.
Do not provide any care if you are being accused of abuse.
No one care what YOUR relationship was with your father, but factual observation can help your mother.
Take videos, when you can safely, of all incidents.
If available to you, document/copy indications of grandchildren taking money.
Use emergency services when “incidents” occur.
Limit your presence to absolute necessity.