My dad kept losing so much weight (hyperthyroidism due to nodules). the internist refers him to a subspecialist. who's are doing nothing, no treatment. i'm very worried for my father declining health. i need real advice. a second opinion?

Call endocrinologist: If a second opinion is needed for a complex problem, you will need to call the Dr directly. Talk to your insurance provider and see who is in network under your plan. Typically an endocrinologist will handle complex thyroid problems, but most Internal medicine Dr's can also have good advice for you. Make sure you father is eating a calorically dense diet (lots of calories per bite).