Is my leopard gecko sick?

They’re nocturnal animals are they not?

They dont actually do much when they get older. Make sure its not too cold in there. Run a warm shallow bath and let him swim as it could be impaction. (a type of constipation)

He may be reacting to a cooler temperature than what he is accustomed to, and the inactivity and desire to sleep most of the time reflects that change. In other words, he is hibernating somewhat, or reacting by becoming dormant. Is your tank warm enough? If he is still eating somewhat and drinking, I wouldn’t worry too much. Just keep an eye on him and increase the warmth in his tank. If he is still like that and stops eating and drinking, you can take it to a vet who has experience in treating small reptiles and amphibians, and ask for his opinion.

@Odysseus He is actually only about 7 months old and he is actually better now. Thank you for your answer, though!!!!