I hope he improves, but you really need to redo his entire setup. His first year of life is when he does his growing and development, and he looks a bit stunted, but definitely has the start of MBD due to Calcium deficiency because he doesn't have a proper UVB tube light or proper temperatures. His basking spot temperature should be between 100-105, his Hot Side between 88-93, and his Cool Side between 75-80, measured with only a digital probe thermometer or a gun, no stick-on thermometers! And he's constipated/impacted because of the Calcium sand, it becomes literally cement when it gets wet. Please, NO LOOSE SUBSTRATES AT ALL!!!! No sand, crushed walnut shells, gravel, pebbles, rocks, nothing but solid substrates like tiles, non-adhesive shelf liner, paper towels, newspaper, etc. So get that sand out now!!!
You need to get him an adequate
UVB light immediately, it's the most important thing you can do to turn his health around, he's not absorbing any Calcium at all because he cannot make vitamin D3 without proper
UVB light. You need either an 18" or 24" long Reptisun 10.0 (never a 5.0) T5 High-Output tube (I would not go with the Reptisun 10.0 T8 tube, he needs the T5 High-Output UVB tube to stop the MBD), and the T5 can sit on top of the mesh lid (the T8 has to be mounted inside the tank) but it must be within 11" of his basking spot. Then the second thing is spending $10 on a digital probe thermometer and getting his 3 main temps corrected, as his temps are too low and he cannot digest his food properly, nor will he have any appetite and he'll continue to become impacted, weak, and partially paralyzed. He needs only the long Reptisun10.0 T5 High-Output UVB tube and a single, bright white halogen indoor flood bulb, 100 watt should get his temps correct, right alongside the UVB tube so he gets both at the same time while basking.