In the letters your mother is receiving from the school district, what do they say about charging your brother with the crime of truancy? She should call the school district (if she hasn't already) and explore getting him charged with the crime, and see what help that would offer in actually getting him to school. Like, it would be great if a sheriff came and got him for school. They do that here -
And I agree with Margy - that counseling is really needed here. Maybe he's developed some severe anxieties or could benefit from group counseling.
Do you live near a larger city? There are charter schools, and online self-paced schools that probably would be more appropriate for him.
Best wishes. It's great that your mother has you to care and seek help.
Has he given your parents a reason why he is unhappy and doesnt want to go to school, was there any bullying you know of, he is very upset and it is possible he would benefit from some counselling,he is acting out , I think possibly your parents may have a parent /interaction problem as it has got so out of hand. A lot of children do not like to be rushed in the morning and it is a cause of many fights between families, I would suggest setting the alarm earlier so he has time to get ready ,maybe go to bed a bit earlier also, and let him get ready at his own pace ,it does sound as if some help is required with his anger, Good luck