When regurgitation becomes serious a large portion of the blood back flows into the chambers instead of going into circulation. Fatigue and chest pressure pain can be the result of the low cardiac output.
If the cardiac output is too low that will eventually cause heart cell damage, then contractions will be weak, and heart failure will ensue. Worst case scenario.
Sometimes the cardiac output is normal, but there are blocked or partially blocked arteries, and because of the occlusion the heart does not get a good supply of blood/oxygen, that could also cause the symptoms described. If not treated, that would also lead to heart failure, etc.
The symptoms can go away and return later with a serious heart condition. Some people don't have any warning or symptoms until there is heart failure and require hospitalization. Your family member should get a check up.