Serious question, my brother has heart issues can he be punched on the chest?

So my brother had a valve surgery when he was 5 years old now he's 14. And he's normal but my question is, can he take punches to his chest? He gets into fights with guys and they end up punching and hitting him he does too. But is that bad can he die? I need serious answers please.
Serious question, my brother has heart issues can he be punched on the chest?
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