tonight when all my family was together for a grill out, he came home after work (hes a surgeon) and while me and my step sister (pregnant, important later) were playing games together in a differnt room. well apparantly he was saying some stuff about his ex wife and her stealing his money (she had just won a court case for a ridiculous amount in childsupport) well. apparantly he took his gun and left.later, after me and my step sister are back in the room we get a call from him asking if any of us had called the cops. thats when we learned that he was at his ex's apartment where there were a bunch of cops. after this, my sisterin law started getting very scared and crying, because he was very angry and had a loaded weapon and he was coming home then. when he got there he started yelling at us, told my sister in law and my brother to "get the fuck out" and when my mom told him that wasnt okay and that she was scared of him after they left the house, he said "good, i dont care" im seriously scared now. im in my room, everyones gone except for me, my mom her boyfriend(who have been fighting verbally) and 2 young girls who are his daughters. them and my mom are who im most scared for. he has also been talking a lot about killing his ex. looking up videos on how to get rid of bodys and we got a "suspicious charge" on one of my  moms cards for a 700 dolar thermal scope which was sent to her house that he claims he didnt get, but i dont belive. we want to get him help but dont know what to do. please help.