Dreading mother's day...

My apologies, but here goes another post on mother's day. In each of my 52 years I've been with dear mom on mother's day. Last month my estranged sister pulled together a last minute 80th birthday party for our mom knowing my husband was on a business trip and I had previously made plans with friends that day. She went full-steam ahead anyway without me. Sister has an abusive husband and seems to re-direct anger to anyone close enough to unload on. I just remove myself from her destructive ways, but my parents are oblivious. Now mother's day is upon us. Mom told me last week she didn't want to celebrate mother's day without both her kids around (as was the case on her birthday thanks to sister), so she just said to treat it as another day. I said OK. I planned to see her the following week and I'm attentive to her throughout the year so I didn't feel conflicted about it. I am happy to spend the day without drama. Now mom just said that sister called and told her she is going to be at a restaurant near mom & dad's house on Mother's day and asked mom to show up anyway. Mom asked if I would go. I told mom I've been trying to recover from a nasty cold (true) and probably would not be there. Mom said OK but she would still go and hung up. So much for parents staying neutral, holding their ground. Sister's manipulations continue. I've posted in a different thread about doing a lot for my parents that I don't think they actually deserve. I'll be having a quiet mother's day with my own family and plan to enjoy every minute of it. I guess I don't have a specific question. I wish as parents no longer do anything for their adult children that we didn't have to celebrate it. Shouldn't it be just for those still supporting minor age children? My mom doesn't do anything for me anymore. Anyway, hope whatever you are doing that it brings you joy and gives you a break.