Is my Broad Headed Skink dying

Question
Hi i have an older skink. he was captured about two years ago by a friend of mine in Arkansas and brought down to Texas where I inevitably inherited him along with a Spiney lizard and Leopard Gecko.

The skink was the most vibacious of the bunch, he would leap into the air to catch his live crickets, chase the little lizard around the cage, and even once had him in mouth. His habitat was ideal for him, he has a 10 gallon tank with reptile safe shredded newspaper, rocks for shedding and basking, vines for shade and a burrow house. I have a reptile quality heat lamp (UV), and a nice automatic water dish. I dust my crickets with calcium and even make sure to gut load them. My crickets eat a healthy diet.

About six or seven months ago I started noticing a more laid back skink. He was not energetic, at one point I even had to hold the crickets in place and practically help him eat them. He would ( lock up ) in these seemingly contorted postions. I thought he died several times; often i would find him upside down in a U shape. The Pet store lady advised me about a calcum deficiency. I believed it was correct because i litterally poured the calcium powder on his head and watched him lick it off his face with no choice on his part :/ He got better but never fully rcovered back to his old self.

Now here is my question: He has been gradually losing weight, to the point now where I can see his entire back bone, he is lethargic, and refuses to die. I feel horrible and feel as if I have tried the best I can. I have never had reptiles before these guys and all I know about them I learned through experience. I have tried soaking him in a shallow tub of warm water thinking he may be dehydrated, he instantly shedded, and looked better, but is still dramatically losiing weight. My Leopard gecko is thriving and I released the Spiney lizard shortly before novemebr of last year.

I am worried about the skink, who's name is actually (big lizard).

any information or suggestions will be helpful and used.

Thanks for your concern, and time.
Crissy

Answer
Crissy, this is nearly impossible for me to answer.  Here's why: your skink might very well be dying of old age-you don't know how old he was when you got him...  OR ...  He might just be sick.  I would suggest you have a fecal float test done by a local vet to check for parasites.  If the test is negative and you're satisfied everything else is ok, just try to make him as comfortable as possible.  If the test is positive you should be able to treat the parasites and get him up and moving again, that is assuming he's not too far gone.  Good Luck!