Should you reward a teen for talking back,down,and telling you NO, and failing school?

My Boyfriend of 8 years has a daughter who won't call him after he beggs her to,he trys everything to be sweet and caring to her but she treats him as though he is a child, tells him NO when he asks her to call him, talks down to him like he isnt good enough and treats him as though hes the kid and shes the adult.She is also failing school and got held back this year and almost got kicked out for missing 60 days,After all this disrespectful behavior and disobedience he is now going to give her a new car with absolutly no responsibilty for keeping insurance on it or maintenance.I am appalled that he would do this after the way she has treated him,to me she should earn a car (a luxury)before being handed one, and that includes doing well in school and respecting her father and not treating him like dirt.I have watched the way she has treated him and it really makes me sad to see him hurt, I feel like she treats him horrible and only does this because she knows he is only going to cater to her, its sick,and I'm mad that he is not laying down the law and standing up for himself.She sends him put down letters and is always preaching to him like shes a adult when shes 15, I believe he is just enabling more bad behavior and irresponsibility buy handing her a new car.When I was a teen had to mind and act respectful and not fail in school before my parents would even let me borrow there car let alone give me one,thats usually a reward for graduation or good behavior and good grades, i feel like he doesnt get that this is just enabling more unruly behavior,All I know is if my daughter treated me this way she would not be getting rewarded for it.He is all the time sad at the way she treats him, I just think he should start being a parent and enforcing some true responsible values instead of enabling the problem. I feel he should explain to her that until she consistently does good in school and starts treating him with respect she will have to wait for luxurys as a new car.I am tired of seeing this child do him like this and him complaining about it all the time,only to turn around and enable more defiance and unruly behavior by rewarding the teen for it.