Having both eyes closed is a big indicator that something is very wrong and he’s ill. The sooner you can get him seen by a vet, the better. Having x rays and blood tested (if you can) will be ideal to determine what is going on and how best to treat him. Some vets will automatically prescribe antibiotics and treat for parasites without proper testing/diagnosing. As these can be very hard on the kidneys, do make sure your vet can tell exactly what the problem is before just accepting these treatments.
An x ray will be able to determine, among other things, the status of his bone density. Based on his casque, he appears to have some history of mbd or stunted growth and possibly a healed burn. His limbs look good though.
Basic blood tests will determine if there is an infection (white blood cell count will be high), organ function, etc.
If you aren’t able to get a fresh poo for parasite testing, some vets are able to obtain a sample from the cloaca.
If his supplementation was lacking, he may need some special supplements from the vet.
I always print out a copy of all of my husbandry to give to the vet to save time and 20 million questions. I also always take any questions I have written down and some paper to take notes of what the vet says.