My fiancé and his ex wife seem to be in denial about some unusual behaviors of their daughter. I have 3 children of my own so I am not new to raising kids. I am also a nurse, so I am sensitive to age related unexpected behaviors and signs of mental disorders. I have tried very hard for the last two years to gently point out behaviors that have become down right embarrassing in groups of people His daughter is 14 and things are really escalating as she gets older. She is lying more and more often, creating untrue scenarios where she is the victim, to her BM. She has zero interest in her hygiene and prefers to be disheveled, dirty and in the same clothing for days on end. Her gums have grown over her teeth due to bad oral hygiene. she crawls on the floor in public places. She has to be first in line, have the front seat in the car and will run people over to get the "spot " she wants. She has little awareness of other people around her, leaving soiled feminine products out on bathroom vanities in shared bathrooms on vacation, (I have a 15 year old son that is absolutely grossed out) she does odd things like stuffing cheese and perishable food items in sofa cushions, people's briefcases, anywhere that does not require her to get up and throw things away as most young adults would. She constantly has items of any material in her mouth and chews them to destruction. She can devour a plastic spoon in minutes. She is completely checked out and her attention can not be obtained, even when shouting her name loudly at close proximity, when she is on any electronic device. She has recently engaged in a "game" at school that resulted in open sores and bleeding scratches up and down her arms from scratching herself with erasers. Before anyone even saw the open wounds she offered a fictitious story that she got them diving for a book. Once the truth was realized, nothing was done and it was brushed under the rug. I could go on and on with the list of unusual behaviors that are completely unnoticed and ignored by her parents. My concern is, is it too late to get this girl help, and if it is done due to my prompting of her father will this end badly? I think I know the answer to that... This is not a new issue and it just baffles me that it has gone on 14 years with no intervention. She has been licking windows and doing very odd behaviors since she was a very small child. Nothing has ever been addressed.
My fiancé appears to be a well put together guy. I say appears, bc maybe I am missing something in a father that doesn't notice these behaviors AT ALL. He holds much higher standards for himself and his actions, than he expects from his daughter. He is very hesitant to "poke the tiger" in his ex wife and he lets boundaries be crossed all the time.He is afraid to broach the subject of the behaviors now that I have pointed them out, to his ex wife. I understand to a certain extent bc his ex is certifiably psychotic, but come on????

Is this just life as a step parent? Do I just have to stay quiet since this isn't my child? I feel this will deteriorate my relationship with my fin ace over time. He thinks I should be more supportive, but I can't b/c the ex wife has told me to do nothing but just be present in the room around HER children. I have already been called a stupid bitch by his ex-wife for giving an over the counter allergy pill to his son. His ex wife insults me every time I see her. I am not sure I can tolerate this forever..... my question is...is this just the way it is when you are merging families?