I have a family member who either doesn't realize the importance of finishing high school or is too lazy?

As a 3rd year high school freshman, on an IEP, what advice would you give to him to deter him from giving up and quiting. This child just wants to sleep through cl, skip school, use reverse psycology to get others to do his work for him. He will flat out tell you he is lazy or doesn't care. I have explained to him that we will not take care of him when he can't get a job. I have explained to him that this is as easy as he will have it in his entire life. He claims that he is depressed, however, his father feels that is just an excuse to get people to feel sorry for him. I have told him it is still possible that he can graduate, though it will be a very difficult road. He claims he is willing to do the work, however, when not in my presence, he boasts about being a slacker. I don't believe any human being is wasted space - but I don't know what to do with this kid. My instinct is a good old fashoned - can't do that anymore. And his father doesn't believe in it. Any advice?