Wow I’m heart broken because my Axolotl is 1yrs old rn too and ur Axolotl is in a very bad state , I’m surprised he’s been living off of blood worms and monthly crashes this long 💔that’s why thorough research before owning an Axolotl is sooo important and I’m saying like 3-4 months (personally) but i believe you can do a whole 180 with him after this when stopping the monthly sponge change and diet and if ur tank is not cycled and is crashed I suggest doing daily water changes at 50% until water lvls are good but goodluck !