My dad is in his seventies, he had a severe breathing problem 6 months ago, and he was diagnosed with weak heart muscles, for which he was described a medication that he needs to take for the rest of his life. Four days ago he started complaining from fatigue, and headaches, and a day after he also started complaining from gastric problems. These are the symptoms that I know of. And I want to know given his previous condition, are these an alarming symptoms