I knew he was a really rough-and-tumble player and then suddenly shifted gears and became a Lady Byng winner, dropping from 154 in 1964-65, to 58 the next season, to 12 the year after that. What I did not know is that he made that abrupt change in his play because his young daughter complained that he was in the box too much.
Apparently he had been suffering from Lewy Body Dementia, a pretty nasty form of the disease. Robin Williams found out he had it, which was reportedly what prompted him to take his own life.