Foot Pain, Diabetic Neuropathy , Stenois In Nerves. Done Surgery. Swelling, Numb. Why Is This Happening?

I m inquiring for my husband. He has had foot pain for a very long time, and alot of health issues, including diabetic neuropathy . But all test say mile neuropathy..and his diabetic doctor even said he didn t think all his pain was from neuropathy. He had back surgery fusing ...can t remember the numbers, but just at the bottom, just above, the S verterbra back in May....He also had alot of stenosis ....He continued to have nerve pain down his buttocks and down his legs. He had injections in his spine , and it also helped the foot pain....which they said some must be coming from his back....They went back in two weeks ago, removed the hardware thinking his body could be rejecting the metal, and also found stenois in some lateral nerves.... His back and down legs are great. His feet are totally almost that he can t walk on them...They did this last surgery.....He says they are swelling...on the bottom, and that they are numb and tingling from the knee down....What do you think???