It could be stemming from a health disorder such as joint pain or a UTI. (Dogs associate the pee pad with pain.) It could also be a behavior issue, (stress, anxiety, fear). It may help to have a health check-up and determine if any changes may have caused stress or fear (loud noises, new people moving in, etc.) If none apply, you may need to go back to basics and restrict his space to the area where his pee pad is, and praise or reward him for using it. Only once he reliably uses the pee pad for several days, you can then give him more freedom. Make sure the area he poops in is cleaned well with an enzymatic cleaner. Alternatively, you can try to keep the bedroom doors closed and see if he goes back to using the pee pads. Pheromone plug-ins may help ease anxiety.