Hello, Your husband is suffering from muscle weakness and extreme fatigue. His blood test and thyroid reports have come normal. Weakness in the legs may be indicative of compression in the spinal nerves especially if accompanied with back pain and trouble with balancing. Weakness in the legs accompanied with numbness and vision problems may be indicative of stroke and needs immediate medical attention. Autoimmune diseases, alcohol related disorders, damage to the nervous system, herniated (slipped) disk, idiopathic inflammatory myopathy, spinal stenosis, etc. Extreme fatigue is commonly caused due to heart disease, stress, anxiety, rheumatoid arteritis, inadequate sleep, diabetes, underactive thyroid, rem sleep disorder, fibromyalgia, food allergy, etc. You are suggested to get your husband get a complete medical health check up done so that the pathology causing symptoms can be detected and treatment started at the earliest. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician