Introduction and please give me advice

I dont know where to turn but i'll try here and hope you guys can help me. Sorry for my bad spelling. 

I am a stepmother to wonderful little girl, she is 2.5 year old and I have known her since she was less than 1 year old. I live with her dad and she has no contact with her mom. Her mom is struggeling with mental illness and ate a lot of pills and used alcohol and nicotine during the pregnancy. 

She is still not talking, when she turned two she could name her dad and the cat but it has gone away. She has her own words for things and do not copy us when we try to tell her what things are called. But she can copy the sound of some words but its just like an echo. 

She really wants to communicate and often leads us to the things she wants and screams at us if we dont do as she wants or she just make sounds, often the same sounds over and over again. She tries to talk with other kids and people and seems to be lonley when nobody understands. There is a lot of frustration, she has meltdowns multiple times per hour some days and just lays on the floor crying or shaking and bangig her head or bites herself in the arms. She is obsessing over thing and can repeat the same routine over and over, brushing her teeth for an hour or cleaning the floor at the same spot but has no interest in toys. She just hold things and move them around the house all day. And we must always watch her at The park or the beach, she jumps right i to The deepest water och jump from high things over and over again.

Something is diffrent with her and she seems to notice that herself and feeling frustrated about it. Her dad do not want to se or just dont know how kids her age usually are. I have been trying to get him to book an appointment because of her not speaking but he has not done that yet.

I started to look at what we can do to help her speak and then The topic autism came up and i can see so many signs that she has it. So many pieces falls in to place and I cant stop thinking about it. But i have not talked to her dad about it. He seems to think that she is just late and a wild child but we need to help her to develop, i think she needs help. Should i talk to him? How would you feel if someone told you that with your kids? What should i do?

I love her and want the best for her.