help! i dislike my step son 😭💔

i dont know what to do! my step son is 4 and very mean to me! he has been very hateful. his father dont do anything and i feel like he thinks i am lying. and his son keeps on because he knows he can get away with it. i have been very patient with him BUT TODAY DREW THE LINE WITH ME! he choked my 1 1/2 year old son so i made him sit in time out! he got mad and told me he will kill my baby(im pregnant) and i told him that was a horrible thing to say to me! then i told him he had to sit in time out longer he said he will call his mama and she will come kill me my unborn child and my son! i am lost! but i recorded it this time. but i still feel like his father wont say anything.