hi there, the symptoms described by you suggest two things,
1.He suffered an attack of angina and prodromal symptoms of a myocardial infarction
or heart attack
as you call it or
and peptic ulcer disease
which gave rise to these symptoms.
You need to get him to the doctor and get his complete physical examination done along with his routine blood tests and EKG, as he is not active a TMT test will also help in ruling out any cardiac ailment besides getting a cardiac echo done if possible. He should be advised to cut down on the smoking
if not totally stop it and get himself evaluated as earlllly as possible. Take care.