Suggest Remedy For Persistent Muscle Weakness With Gout, High BP And Diabetes

My 60-year-old husband has suffered from muscle weakness for many years, and it has gotten a little worse in the last 5 years. If he walks more than 100 feet or so; has to stand for a short period of time, or does anything the least bit strenuous, his legs get shaky and he has to sit down or use his walking stick. He has fallen a couple of times as well because of it. I have also noticed that his hands sometimes shake a little if he is doing a task that requires a certain amount of dexterity (like shelling crabs). His mother once told me that he was born premature, and that his muscles did not fully develop, whim is what causes it, but I have known him for 34 years and I did not notice this problem until about 17 years ago. Sometimes his lips quiver some when he talks and he did tell me that he had a bad stuttering problem as a child. He and his primary care physician seem to think these things are normal for a man his age, but I do not and he seems unwilling to go see a specialist (not sure what kind he would go see). His doctor did mention having a nerve test, that he had done many years ago when he had tingling in his hands and he said it was very painful and he would never have that done again. He also has gout, high blood pleasure and type 2 diabetes, but all of these are well under control. Any idea what may cause this and how can I convince him to see someone who may help?