I'm afraid the photos aren't showing but I'd recommend getting him off the tortoise life and onto sterilised topsoil. You need to increase his basking temperature to 32-34 degrees.
He needs calcium on his food more often. I use limestone flour 5 days a week and nutrobal twice, so supplements every day.
He needs warmth and light to wake up and eat and the warmth is important to aid digestion. Time outside this time of year is beneficial. Does he have an outdoor enclosure?
I'd also possibly consider running a wormcount on him.
www.wormcount.com are great for turning results around quickly.
Good luck with Sheldon. A few tweaks there and there may make all the difference.