I need help!!! my dad is trying to sue my boyfriend can he do that?

my mom gave my dad temporary custody for 6 months however i lived with him longer. legally my mom had custody after the 6 months ran out. My dad is abiusive and gets violent alot so about 7 months ago i ran away to alabama to live with my mom which my dad could not do anything about. well my mom was unstable so my boyfreind came out htere and we lived on our own for 5 months. His mom got sick so he came back while i was working to save up enough money for a ticket out here. well my mom gave me permission to live with him but i was scared my dad would harrass him and his parents. therefore she gave me a notarized letter allowing me to live with one of my friends which is right down the road. hhowever i thought it was nonsense to live right down the road when i am with my boyfriend all day every day and he takes care of me so she gave me permission to move in with him. after i moved in i started talking to my dad alot. I felt bad. he told me that whatever i chose he supports me now. Well on father's day we went to our old church which my dad has recently started going to put a show on like he is a changed man...... well my boyfriend,his dad, my dad, his girlfriend, pastor and the youth pastor and i had a talk.my dad said he does not care where i live as long as it is not with him. they talked so down to him, but anyways the talk escalated nd my dad threw the card i got for him at me and stormed out. his girlfriend started screaming at us that he is going to get custody of me and she is going to sue him. What can i do??? i do not want him in trouble for me and i just think this is nonsense. i am 17 and he is 20 , i live in Arizona.