Concerned about my best friend

Alexandra • Smith College 2023. Bi, Canadian, in a committed relationship.
Please read the whole post. Note that this is more about Bianca's mental health and family situation than gender identity, although it definitely plays a role in her family life. Please don't be hateful.
My best friend, Bianca is 16, pansexual, and recently came out as transgender ftm (he hasn't chosen a new name or transitioned to a boy yet). He is also adopted. Bianca's parents don't accept him for who he is so he has a lot of trouble at home. His mother won't let him transition to a boy's body and pressures him to keep his girl clothes and name. His parents never hit him, but his mother is very manipulative and his father is almost never home. His dad goes to work in DC all week and is only home on the weekends. When at home, Bianca often has anxiety attacks and emotional lows due to depression. He was even in the hospital for eight days suffering from suicidal thoughts, which caused his grades to drop. His mum blamed him for the drop in grades and told him he isn't allowed to socialize. His mother is very controlling over his activities and doesn't seem to understand him; when they talk on the phone, she often jumps to conclusions and yells at him. This makes him very upset. He reports every day to me and his other friends of the terrible things she says to him. Last week he told us she was demanding he say "I love you" and when he didn't say it, she got mad and said, "why are you being such a b*tch?!" His sister (also adopted) is very kind and loving and accepts him. She has told him that their mum said something along the lines of "she (referring to Bianca) won't be able to get a job, so you (his sister) will have to." We live in New Jersey, U.S. and I have read the state law in emotional and verbal child abuse and I think this qualifies, but the adults in our lives are telling him he needs to accept it and that it's not abuse. I cannot accept it, although he has resolved to denial and sometimes shutting his friends out. I try to provide him with the information he needs but it's very difficult for him to accept it. This is greatly affecting him and it seems like it's getting worse every day, but no one outside of his friends seems to think something needs to be done. I can't give up, turn a blind eye to this. He's clearly getting hurt and I don't know what to do.
Additional info (update): Bianca has been seeing a therapist and takes medication for depression and anxiety, but his mum sometimes won't let him go to therapy or won't let him take his meds. She blames him for everything and tells him he will go to hell. He has turned in applications for jobs, but is waiting to hear back from the employers. He is also trying to get emancipated so that he can do his transition without his parents' consent.
What I want to know: Do you think his home situation could be causing his mental health issues? Is this situation considered abuse? If so, should I report it to the authorities? Is there anything else I can do? Please give reasons for your answers; I am a logical person, so I can't operate without them!