Hello and thanks for writing.
I can understand your concern and would try to help you in the best possible way. Your dad has a history of coronary 
artery disease with low 
Ejection fraction. This means that his heart is weaker than normal and can pump with 38% efficiency. A normal heart can pump with around 55-60% efficiency. 
This puts him under risk of 
chronic heart failure in the long run. He would require extra care which includes:
1. Keep a strict water intake and output balance to avoid fluid built up in the body.
2. Reduce daily salt intake to less than 2300 mg/day.
3. Take regular exercise being careful not to overexert. A sing test is very convenient way to test this. He should walk or exercise only till the time he can sing along. If he has any breathlessness doing it he should stop immediately to rest.
4. He should take certain medication which reduce long term mortality like beta blockers, 
aspirin, statins, ace inhibitors and others. Consult your cardiologist regarding this.
5. Any 
chest pain, palpitations or 
shortness of breath has to be evaluated with a physician.
As far as left nipple burning is concerned it could be a local thing and would be advisable to be followed up by a doctor.