Well at least he is eating, thats good news as he is not too ill to eat. Do you have any angling shops you can purchase worms from? Pieces of meat are ok occasionally, try something like squid if you can as well. Buy it from a fishmonger and cut it up into small strips and put them into ice cube trays with water. They'll keep well this way (but will make your freezer smell a little(!).
I saw your thread about his skin, it looks like excess mucus which could be a sign of bacterial type skin infection, but is also created during heat stress or even general stress. It can also be a problem with shedding.
I would worry about his weight first as his excess slime secretions could be due to his previous stressful conditions. If under better water and housing conditions and better weight he still shows this excess secretion then you can investigate further.
Good luck, keep us posted in the next few weeks (he does look like a handsome axolotl and will look great when he's better)