You don’t have to be angry. I find for myself the strongest feeling is deep disappointment. I would rather distance then engage in toxic interactions. I was betrayed badly by an older sister I thought was safe to love and trust. Well, it turned out that she was extorting thousands from my parents and lied to them in telling them it was me. I was very close to my parents and was devastated when I learned how she was gaslighting them to not trust me.
I pray they are in heaven and know the truth. I learned that you can love someone who will rip the rug out from under you even though they are family.