How wonderful! So glad he's doing better.
If you are looking for a stable, washable, and supportive flooring for any special-needs related conditions, sheepette would work well. It can be better than a large fleece blanket since that might shift around more: https://www.amazon.com/Essential-Medical-Supply-Sheepette-Synthetic/dp/B001CBG14U/
I have it for one of my buns space due to front paw complications. You can cut it to size and also throw it in the washer. Spot cleaning with vinegar and water works well too.
Essential Medical Supply Sheepette Synthetic Lambskin, 24" x 30" https://www.amazon.com/dp/B001CBG14U/ref=cm_sw_r_cp_apa_i_K.0PDbFT0TDJJ
Something like that?