RIP for the guy. Another death for boxing, another day of mourning. What could be possible changes in boxing to avoid future casualties? Boxing is a sport for the warriors though. These guys know that death is always in play once they enter the ring either for a real fight or a sparring session.
I don't think we can avoid it, boxing organization is doing everything they can prior to the fight, test and everything to see how healthy the boxer is. Maybe reducing the rounds again? but it won't be as competitive.
It's inevitable, there will be always some cases like that every once in a while. In the world of combat sports, the risk is always there and safety is not guaranteed, they may try to reduce the risks but they cannot take that factor away. Promoters, organizers, and fighters/boxer know that fact but they still chose to move forward because of the reward that they could get every fight.