Suggest Treatment For Chronic Foot Pain

I am asking a question that pertains to my father. He is 95 yrs old. He has had chronic foot pain for several years. We have had him to a podiatrist, FP,a neurolgist has checked during a hospital stay,and he has had a treatment where they expand the blood vessels in the legs. The pain is primarily at night, but also troublesome during the day. My stepmom treats them with absorbine jr, which helps just a little. The last week he has had no relief and spends most his nights awake in severe pain. His feet jump from the shocks in them. We don't know what our next step should be. He is not diabetic.