Hello I have gone through your question and understood your concern. Pain in the legs can occur as a result of conditions that affect bones, joints, muscles, tendons, ligaments, blood vessels, nerves, or skin. Leg pain can occur at night, while lying down, or while running or exercising, depending upon the cause(an in jury or a chronic disease.) Since the leg contains a number of different structures and tissue types, a wide variety of conditions and injuries can cause leg pain. In your father s case ,in my opinion the cause can be Diabetic neuropathy (nerve damage from diabetes).This is a common cause of leg pain in diabetics. Anyway my recommandation for you is to consult his doctor because for diagnostic and therapeutic purposes, it is important to differentiate the exact type and location of his pain in the leg. Apart Diabetes other potential causes of leg pain are:Peripheral artery disease ,Blood clots (deep vein thrombosis), arthritis conditions, The pain of sciatica (from disc disease of the spine). All these alternatives should be taken in consideration for the right diagnosis and only after the righnt diagnosis your father can have the right treatement. Hope this is helpful. Thanks for using HCM for your health queries. Wish you all the best.