I don't know if this helps(i'm sure you are feeling pain for your father) but my wifes Dad,who lives here with us in a 2 bedroom home addition on my property,suffered his second heart attack last year and they had to do quintuple bypass and install a new valve(pig valve no less). He is doing fantastic and is expected to get at least 20 years of life on the surgery.
He is 80 years old!
Modern medicene is wonderful.
Keep the faith and be strong for him. He needs you to do that to help others in the family be strong too.