Jack Hogarth, 15, was assaulted outside a Dundee school after sitting his English prelim exam in January, and was left with concussion, a broken nose and broken fingers. The pupil who launched the attack outside the school received three days' suspension.
Family GP Michael Clinch examined Jack and concluded that he was psychologically unfit to go back to the school.
Dundee City Council has refused to pay for home schooling, meaning the S4 pupil has received no formal education for almost five months, despite being in the middle of his exams.
Dr Clinch told Michael Wood, Dundee City Council's director of education, in a letter that the school was "clearly not a safe environment for Jack at present". "As far as I can see, home schooling is the only option feasible," he said.
He added that the school was "unable to control this child and unable to exclude him. Jack's education is suffering as a result".
But Jack's mother, Louise Hogarth, 43 "It's an absolute joke, a total nonsense. The boy even admitted doing it, they just have no powers to exclude him."