My Dad Is Diabetic Patient Since 28 Years.he Had Heart

My dad is diabetic patient since 28 years.he had heart attack in 2009.2 veins were blocked at that time. But since 2 months he starts feeling pain in chest doctor asked 4 ECO test. Reports says that his heart is functioning only 45% and segmental wall abnormalities has been seen. He is a strong will person but very short tempered he daily go 4 walk and avoid the things which are harmful.I just wanted to know the treatment of increasing his Heart function and precautions