Are you willing to get the Covid vaccine when offered?

It's a near statistical probability that he will be exposed to COVID. And one of the side effects of COVID is inflammation of the heart. In fact you are more likely to have heart inflammation from COVID than the COVID vaccine.

Overally, he is far more likely to die from not getting the vaccine than from getting it. Just like almost everyone else.
But we can limit our exposure to COVID and apparently, he has done a good job of doing that over the past few years. So right now, the vaccine poses a higher risk because he currently has a bad heart and he would have to catch COVID first for that to actual pose a threat. Because of his condition, things aren't looking good if he catches COVID, regardless of being vaccinated.