Possible brain damage to the son caused by boxing?
Over time, the term “punch-drunk” was replaced by “dementia pugilistica” and eventually "chronic traumatic encephalopathy (CTE)." Its symptoms, depending on the sufferer, include slurred or garbled speech, unsteady gait, tremors, loss of analytical ability, memory loss, mood swings, irritability, confusion, depression, and erratic violent behavior.
https://www.boxingscene.com/damage-untold-story-brain-damage-boxing--157578