I'd moderately guess a blend of four and five. A lot of confirming five is knowing what the man needs assistance with. For example, if he has trouble finding a bathroom in the White House, I'd say he's easily at five. The stumbling over his words, dropping sentences, forgetting where he is, that's all stage four stuff. For a normal old person, they'd just ask a nearby friend or family member, but when he's on camera, he can't do that. I'm leaning toward five, though.