Toxic parent?

I’m needing advice. My husband and I have tried to be patient and understanding towards my mom, but she continues to antagonize us and is very emotionally immature and volatile. We can’t take any of the negativity much longer.

Do any of you have a parent who is very unhealthy and negative? What have you done as far as maintaining a (relatively) functional relationship with your toxic parent? Or do you not have a relationship with them at all?