Yep, that sounds like a heart attack
(or myocardial infarction
if you want the correct terminology).
He needs an ECG test (or EKG if you're American); the electrical activity will determine the extent of the attack. If that comes up normal, then I suggest a nuclear medicine stress test
to assess the blood flow to the heart. Any cardiac tissue that has scarred will not show any blood volume, which sticks out like a sore thumb on these tests.
Get him to have it assessed sooner rather than later - it might just save his life.