Can I sever Ties With My Selfish Sister?

Can I Sever Ties With My Selfish Sister?
The magazine’s Ethicist columnist on whether to renew a relationship with an estranged sibling.
Several years ago, I told my sister that I wouldn’t be upset if we never spoke again. Recently her husband, with whom I have a good relationship, asked me to reconsider. I’m torn. I don’t want to have any contact with her, but I don’t want to deny my two adult daughters contact with the only family that exists on my side.
Growing up, my sister and I experienced daily physical and emotional abuse from our mother, who was prone to frequent outbursts of terrifying rage. (My father was the invisible man, allowing her ego and anger to run amok.) Today I am in my early 70s. My sister is a few years younger. We were never close but we used to get together for holidays. We live hundreds of miles apart; my sister remained in the city where we grew up and where my mother continued to live after my father passed away.
Some time ago, my mother ran into health problems and was hospitalized. My sister told me that she had done her part and that now our mother was my problem. For a year, I traveled back and forth every weekend to deal with my mother’s health issues. Then I moved her to a retirement home near me, and until her death made hundreds of visits to see her there and in the hospital.
Throughout this period, my sister’s behavior was appalling. Before I moved my mother, she divided up her jewelry, taking everything of value for herself and leaving my two daughters with leftovers. (My sister said that as my mother’s only daughter she was entitled to the jewelry, and my girls should be grateful that they got anything.) When I wanted to arrange extra care for my mother, my sister said I could pay for it; she wasn’t going to allow me to piss away her inheritance, which was not substantial in any event.
After my mother’s death, I found the stress of dealing with my sister’s self-absorption and anger increasingly difficult. I know that my sister has her own legacy from our traumatic upbringing; she has talked about having been in therapy for decades. I’ve told my daughters that I absolutely don’t want to stand in their way if they want to interact with my sister. They have spoken with her a few times on the phone but found the calls awkward. My stress level is definitely lower without having to deal with my sister, but I wonder if I am being unreasonable about this. Name Withheld