Good Morning All. Gosh haven't been on here for years. Lots of lovely cockers still here

My boy Robbie is 14 in Jan and has had been a happy healthy dog for all these years. We have been lucky. He started to have some bouts of diarrhoea and was getting us up in the night frequently. I thought it was due to the first time ever bout of fleas he got. Anyway cleared those but he just didn't seem 100% and his breath was vile. I put this down to bad teeth so off we went to Vets. Sadly nothing wrong with his teeth, but more sadly his blood test showed kidney failure. Nothing they can do to fix. But we can do our best to make sure Robbie is looked after. He was so poorly at the weekend we thought it was time to say goodbye. Miraculously he turned it around and sprung back to his usual self.
Robbie is eating / drinking as normal. Still likes his small walks 3 times a day. He is happy. I know this can very quickly change and will do what's best for him ultimately.
So Vet has told us to change his food naturally to a Kidney / Renal type one. He has suggested
'Hills KD' or 'Purina NF Renal'. We could only get the Purina one yesterday quickly and he loves it.
I was wondering though what others have done and if you could please guide on treats / fresh food / renal food.
In addition - what lies ahead and what can I expect. He gets me up in the night some nights, not every night. He is pooing ok but it does have a bit of blood in it. Not loads. He is weeing normally, not too often or little. He doesn't drink more often but when he does its loads.
Thanks in advance
Robbie and Robbie's mum xxx