I'm so sorry Melo is not doing well. It does sound like he may be at the end, from the description of his current condition. If you can bring him to a vet or ER vet now, he might get some sub-Q fluids or I.V. fluids that may help.
I know how difficult this is for you, but you have to hope for the best, ***** ***** prepared for the worst. Remember, that you want him to still be enjoying quality of life and if he is not, it would be out of your love for him, and with the agreement of your vet, that he is put to sleep if nothing further can be done.
Kidney disease is an awful thing in cats when it gets to the end and if the vet who sees him in person tells you there's nothing more to be done, you'll have to make the dreaded decision so he does not suffer.
I send all my best thoughts and prayers to you and Melo.
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