WIBTA if I didn't let my sister give part of my inheritance to her son and his wife?

This one has some history to it so be prepared.My mother has dementia and her time is nearing its end. I've had a very long time to prepare for this (decades) so I'm doing okay. Also, my mother and I are not close and I am estranged from my family. She has a sum of money in her bank account that will mean that those who inherit will get somewhere between $20k and $30k depending on how things are done.Now, for the history. I have 3 siblings (sister, X, 12 years older, brother, Y, 11 years older and brother Z, 10 years older). X was given the ability to act in a primary caregiver role, almost as a mother figure who would discipline me. This turned into emotional and psychological abuse quickly.So, fast forward and my brother, Z, is diagnosed with stage 4 colon cancer. I was starting a freelance journalism career that I put on hold to help him (we both lived with my parents). My brother passes away and at the funeral my sister says to me, "I wish it had been you that had died rather than Z. Z would have taken care of Mom and Dad." I then make the decision to take care of my parents for the next 10 years.Before my father died, I made sure to get his veteran's benefits and they came through a month before he died. They went to my mother which made me glad. It wasn't much but it ensured she wouldn't want for anything. At that point her care became more than I could handle so we put her into a care facility and the benefits went largely untouched as her own retirement income covered most everything.So now we're coming to the end of my mother's life and my sister has taken over as the lead in her care. There's not much to be done except visit and keep in contact with the facility. My sister started making plans about 5 years ago about the inheritance. She wants to split between myself, her and Y as well as giving a stipend to her husband (for various chores) as well as a portion to her son and his wife (I don't have kids and neither does Y).I put my foot down and said no. When I was caring for them for those years she did nothing except a family dinner once a week. When I had no money for food, she sent me to the food bank.I now live on provincial disability while she and her husband (both essential workers) make a 6 figure income between the two of them that allow them to travel to Europe (pre-Covid) regularly. Even taking her son and his wife with them.So, AITA for not giving a portion of the inheritance to my nephew and his wife? via /r/AmItheAsshole https://ift.tt/37pWrNP