My 19 yr old nephew was a collegiate athlete who died suddenly when his heart failed after a baseball game (not known if there was blunt force trauma involved). I had my 2 boys (also athletes) tested with echocardiograms and EKGs prior to engaging in high school sports, and we got through it.

Relatively rare occurences and poorly understood, but basketball players seem particularly vulnerable (Hank Gathers, Reggie Lewis and others). I'd say that given the odds, Bronny James' basketball career is probably over (sadly).