I have Hypertrophic Cardiomyopathy
. I don't know if that is the same kind that your father has, but it is characterized by a thickening between the two chambers of the heart. There is no cure but there is medicine to help keep it under control. Sometimes if the muscle gets too thick heart surgery is necessary, but don't freak out yet! Ask your father how bad it is. Sometimes you can live a completely normal life with it. However, strenuous activity is not really a good idea with HC. Strenuous activity can make the heart race and cause a electrical problem within the heart which can cause fainting
or perhaps more.