You could tell your mother what you are considering doing and why to see if she is willing to curtail her bad behavior. If it persists after that, you’ve been candid with her and given her a chance. At that point, you could have family gatherings without her in peace. I know she is your mother but there are other family members involved who deserve to have a family event without the memory of the fiasco your mother turns it into. Is she an alcoholic? Is she willing to get help? I hope you come to a decision that brings you peace and healing.