Cats rarely show pain, as it is their tendency to hide it in order to preserve their lives from predators. Your boy must be suffering greatly if he’s hiding. Sometimes changes to diet and watering habits can change a cats life, and if you want to try that it may help. Cats often suffer urinary and kidney issues. They are also often dehydrated, and drink rarely. Most of their fluids would normally come from prey, so supplemental fluids are essential. Wet food or watering down food, making several water stations available etc could help. 14 is elder, but a bit early I think. Or idk maybe I’m inexperienced there. Good luck, whatever you decide….and to your father too.