If a trust says we cannot contest will any of my siblings be allowed to sue?

my sister threatens to sue me saying I kidnapped my mom. also she tried to get me to court with alienation of affection. shes the one who closed one of my moms accounts and tried to get my brother off as executor and tried to put a house up for sale with no authorization. my mom left to live with me in nc. her free will because my sister left in a huff because she could not sell all of my moms homes. at that time my mom lived in fl. my dad had passed when this all went down. help. I do not want to go to court when I was doing the right thing. 2nd question does my mom need to put our names (4 siblings ) on the deeds to 4 homes even if we have a trust?