I've never felt so scared/so alone in my life

I just watched my dad give my mom the Heimlich maneuver and I had to call 911... I've never had to call 911 I'm literally shaking She's breathing and my dad canceled the ambulance but she is still coughing and my dad is helping her and I'm just in my room crying cause I don't know what else to do. This is the 3rd time this has happened with her this year. They don't know why but she chokes easily. My dad is a nurse anesthetist. She is stubborn and won't go to the hospital. I think she should because it could happen again.