From what I hear, he's doing the Charlemagne thingy. I think the man will not stop working as long as he can breathe. They'd just have to make sure he doesn't have to travel. Not that he couldn't travel, but..he's 89. Just let the guy go home to his wife at the end of the day and he'll likely at least consider the offer.
Hell, I bet he would love to do it. He doesn't want to be remembered just as Dracula, so he'd likely give such a performance no one would dare touch the role in eons.