Babies do sleep a lot, however, you need to post pix of your setup and your tort complete with temps. That way we can really help you, by knowing how he is kept. Is he in a closed chamber???
I don't guess you should be worried, but let's fix the problem before you DO need to worry....
More information would help us know if you need to worry or not. If temps and everything else is ok, then babies sleep a lot. There could be other issues though. Pictures are very helpful too.