aww its heartbreaking when the time comes, but i have lost one of my previous girls to renal failure, to be honest she was gradually thinning down & drinking lots more water, the vet said it would be a gradual process until the kidneys were at a point when they could no longer cope & then things would happen very quickly &i would know it when the time came.
unfortunately he was right after a few months, because within hours she went from coping to rapidly deteriorating & the final act of love had to be taken
is the vet sure its renal failure & not just a bout of cystitus/urinary tract infection? has he been tried with antibiotics to see if it will clear up?
if he is very wet, i used to give mine daily bum baths & just trim away her hair near her genitals to stop the hair being wee'd on & smelly (needs to be clean this weather with extra flies about).
make sure he is thoroughly dry before going back outside though.
quite often heart & kidney issues are linked, is there a possibility this could be happening in his case?
what tests or observations did the vet do/see to conclude with renal failure?
i read somewher that cornsilks (stringy bits off of maize/corn on the cob)were good for kidney problems also cleavers or the sticky bud plants goosegrass whatever you want to call it - preferably before they get the little white flowers on them.
give him foods such as cucumber to increase his fluids & try some dandelions/celery if he is starting to retain water , unless he is really bad & the vet or diuretics are needed.
its a fine line to balance all the levels.
@Adelle has had experience with this & has some great information on potassium levels etc that may help your little man
@helen105281 has a good diet for IC piggies would this be of any use to try for him to see if he improves?
good luck & hopefully he will go on with a good quality of life for a bit longer yet, but please dont dismiss the UTI possibility of it
xx