My 16 y/o brother refuses to go to school. My mom is dead and dad could care less, I NEED ADVICE!! HELP!?

My mom died suddenly in January , and my 16 y/o brother has refused to go to school since then. He had my dad buy him all these school books and pay for an "online high school program" My dad thought he was doing the school work. I called the school yesterday, and they said they have not received one thing from my brother. The school said he has 1 year to complete prog. before they drop him. I told my dad, and he told my brother he now has to go to public school. My brother flat out refuses to go. Truency officers won't do anything, because technically, he is inrolled in school. (online) My dad treats it like it is easier to ignore the problem, then deal with it. Can anyone help me? I know my mom would be so sad to see my brother drop out of school at the age of 16. Any advice ... please. Oh, and my brother refuses councing.. We can't even get him in the car to go to a dentist appointment if he does not want to go!! HELP!!!