tbh, I don't know how much growth there's actually going to be for him. They can't exactly have too much happen with a 50 year old infant in just a few seasons of a show.
Amphibian genocide antics notwithstanding, he's already demonstrated that he's probably more mature than he seems (what with the healing and the awareness to close his pod before shit went down in the previous episode), so I have no idea what (if any) plans they have for the character going forward.