Grimple, I'm sorry to hear about your husband. In addition to medication, exercise, and diet, your husband may want to look into getting psychiatric help if his depression persists. It will help his life expectancy.
This may sound like a random question, but has your husband seen a dentist recently??? There is significant evidence suggesting that periodontal disease (inflamed gums/receding gumline) increases one's risk of a heart attack.
Best wishes to you and your husband!
Dental infections can be good predictors of bacterial endocarditis and associated valve infections that can lead to heart problems, but I don't think this is likely to be the major issue here (and any cardiologist would check this).