My Dad just sits on the couch all day and sleeps. Should we be concerned?

I can understand your concern. The first thing I'd do in you place is get him a thorough checkup. If there are medical conditions contributing to this lethargy then addressing the conditions is at least part of the solution.

And it should include a complete blood count. Those can show many possible issues. Maybe he is bored and needs some activity. Is there a senior center or day program that he may have some interest in activities? Did he play pool, darts, cards? There are leagues for seniors and some centers have the equipment and groups that get together.

Lethargy by itself is rarely an emergency, however, if it is persistent or is accompanied by other serious symptoms, you can speak to your physician. I agree with gladimhere, it could also be because of boredom or slowing down of the body cycle.

While there will be medical reasons a person will slow down, I would never consider it normal. When you are carbed-up and full of energy, you LOOK for things to do, even if you dont know what that is yet. Altering the diet and amount of sunshine he gets may encourage interaction. Sounds too simple to be helpful but when your body WANTS to move, it doesnt take no for an answer. Our brain is like that with stimulation,too. Sunshine and high carbohydrates act like a domino-effect on every other issue that needs addressing and softens them.

Low thyroid, depression? Make sure the doctor knows what he is doing, so many times the patient does not say anything.

My mum has diabetes and she has become like this also recently although she is only 76yrs I think diabetes is the main cause as they do deteriorate get his doc to test his sugars also my mum is bored stupid ive tried everthing and have given up. I have heard here and in alot of countries about "the mens shed" could there be one in your area its where retired men hang out and talk and learn new skills? Is he mobile ive heard this mens shed is great!