I read your query and I am sorry about what you are going through.
From what you are describing he has had a
severe stroke involving a large area of the brain. The fact that you say his right pupil is large and unresponsive indicates a big lesion with edema which is compressing his brain stem and if the pressure augments even more it could be fatal. Unfortunately right now as your doctor has said you should just wait for the edema (swelling) to stop and then gradually subside, even in the best case scenario it won't happen in one or two days, could take several weeks. Also there is also the risk of other non neurological complications which could present in many intensive care
unit patients, like for example infections which in his critical condition are more likely to happen and difficult to treat,
pulmonary embolism etc.
As for the long term, that is in case he survives this critical phase and recovers consciousness, you should understand that most probably some residual
disability will be left. Some part of his brain is irreversibly dead, given the stroke gravity you're describing that is for sure I am afraid. I am not saying that improvement is not possible, but it will depend more on the undamaged areas compensating for the lost ones. How much improvement there will be varies, even for the same stroke size and gravity it may vary from one patient to the other. What you should understand is that it would take several months and it will be more a question of prolonged
physical therapy rather than miracle working drugs.
I hope things will work out for the best.