Nat did some more walking and he was throwing a ball with his physical therapist. And, in excellent news, which I got in a roundabout way from MeeMaw through Aunt Janice, he requested to use the potty, and was able to. Which I know doesn't sound like a huge deal, but you have to know Nat. He was potty trained pretty early on and he was very meticulous about being a big boy and going to the potty all on his own. I can only imagine how relieved and delighted Brian must be to see Nat turning back into the boy he was before all of this.
The chemotherapy will probably start today, which Mom thinks will sap all the strength Nat has gained since the surgery, but as hoppie points out, better he have some strength to be sapped than nothing and less than nothing after the chemo.
Edit: And one more thing, which may or may not be encouraging. When my parents showed up at the hospital, he called them by name (Softa and PopPop) and did not tell them to go away as per usual, but seemed happy to see them.