re: Most dangerous era of football with actual helmets?

Know a man who played football for Tulane in the early 50’s. He’s still alive but has horrible knee and hip problems, and now has a very bad case of Alzheimer’s. It’s really sad to see but I’m sure it’s from playing football in the era that he played in. Can’t even imagine lining up against someone with the kind of helmets they had back then. I’d hurt myself playing football with modern and safe helmets, can’t imagine how it was back then