I'm sorry about your FIL.
I am not trying to scare you worse but your DH is at risk. Heredity is a huge risk factor, and unfortunately for your DH, with his dad dying so young, his risk is even higher. Adding in other factors like obesity increases the risk.
If your DH hasn't done so, he should go to his doctor have a frank discussion, get a work up and a treadmill stress test.
Please take this is in the loving way I intend it.
:grouphug: