No cause of death or vax status, but he was only 31 and a Fire Fighter/Paramedic in Lewisville so we expect he was in good health. Too many healthy, active young men are dying suddenly; could a reaction to a recent vaccination be the cause? If so I hope that information will be entered into the VAERS database.
Most firefighters get an annual physical including cardio.
As much as I love and admire my 1st responder son-in-law, he is fat, out of shape, and a heavy smoker. Don't assume anything.