Glioblastoma is a malignant tumour arising from the supporting cells of the brain. I am sorry to inform you that it is a nasty tumour with a generally poor outcome in terms of long-term survival.
Exceptionally, a glioblastoma may respond to radiotherapy/chemotherapy. This is the reason why these forms of treatment are employed.
He does need physical training to help him reduce the handicap imposed by the damage done to the brain by the tumour.
You are already doing everything possible to help your patient. He is being treated at one of the best hospitals in the country by doctors who have massive experience in this field.
Your doctors will watch his further progress and the effects of therapy on the tumour.
If, despite all measures, the tumour continues to grow, spread to other parts of the brain and cause severe increase in pressure within the head, the outlook is grim.
I am sorry I cannot be optimistic as the nature of the tumour is bad.