I presume the clotting of blood in the veins that drain the brain involves the left half of the forebrain or cerebrum. Much will depend on the extent of permanent damage done to the brain by the clot and by the interference with drainage of blood from it. If the permanent damage be small and most of the present abnormality be due to compression or swelling, he should make a fair recovery.
It is important to determine, if possible, why the blood clotted in the sinus. If the cause can be uncovered, steps can be taken to prevent recurrence of the thrombosis.