Something is missing here. You mean he fired the rifle last year, and you are just now getting around to opening the bolt to extract the fired case?
Or are you saying that the rifle worked OK before and after the hunting trip but after being stored for a year the bolt will not open?
If the former, shame on you. If the latter, I suspect that during the hunting trip he got some moisture or even blood on the rifle and the bolt is rusted shut. First, make sure it is not something simple, like the safety being on and locking the bolt.
Then, if that is not the case, remove the action from the stock and soak the bolt and action it with a good penetrant for a day or so. Use a block of wood to try to hammer the bolt up and open. Use moderate force and I think it will open.
Jim