Am i crazy?!?! (my dad :/)

when i was 7 and my sis was 14 he got remarried (i luv my stepmom and bros). my sis got fired over a whole ass lie (thd boss/guy who fired sis is my stepmoms bsfs brother) and unfortunately she (stepmom) took his (boss) side. but here the part that makes me mad…MY DAD TOOK HIS WIFES SIDE OVER ME AND MY SISTER!!! i nd my brothers were there the whole incident and she literally did nothing wrong but my dad refuses to even acknowledge it happened. he also yelled at me for an attempt saying stuff like “how am i supposed to tell your mother about this? you’re getting me in trouble with her”. he is kinda trying-ish but i feel like it’s too late for that….my therapist says i should take him to a session but i feel like its a waste of time and money. am i crazy???