I'm sorry that your father is going thru so much. I don't have any advice for you as this seems to be heart related. I know that when someone has heart issues, it can make them very tired as well as the medications they take for it. Perhaps you can try our Heart/Cardiovascular forum to find the answers you seek?
Moderator-Allergies/Asthma and Alzheimer's, Co-moderator-UC
Diagnosed Left sided UC in '92 - meds: 6mp, Colazal, Remicade and Bentyl*Unable to tolerate ALL mesalamines*, in '11 diagnosed with IBS, Diverticulosis, Fibromylagia..I also have Sacroiilitis, Scoliosis, Raynauds, OA, PA, Rosacea, Psoriasis, Dry Eye and allergies controlled by Zyrtec and Singular