Sadly things took a bad turn...
I noticed after walks he seemed pretty tired and in the evening a bit uncomfortable. I took him to the vet on Thursday for recheck of his UTI and stones. His UTI seemed to be resolved or resolving and the stones were lesss numerous. We kept him on Clavamox nonetheless for another 10d in case the stones released more bacteria or the infection wasn't 100% subdued. He didn't eat as much on Thursday evening, even less so on Friday morning and seemed a bit lethargic. Friday evening he wouldn't eat but a little kibble. He threw up in the early morning and appeared to be in pain on Saturday. I took him to the ER vet hospital and he was diagnosed with pancreatitis. The hope was for pain meds and fluids and pancreas to heal itself (interestingly his white count was not high, almost as though his immune system wasn't really working). But unfortunately by Sunday morning there was septic fluid about his organs. I took him home and he passed away peacefully in the afternoon. It is really, really hard. I think so much the harder as with his diabetes and Cushing's he required lots of care, he was my world. Despite all that though he survived long and was stunningly active until the very end.
Thank you for your advice over time.
Kiwi - male Schnauzer, 2yrs Cushings, 4yrs diabetes, 14yrs 3m on passing on 6/21/2020