When Morgan had his op last year to remove struvite stones the vet asked what he was fed on. At the time he was on Burns kibble which the vet approved of, in his (approximate) words -
"That's one of the good ones for bladder health, there are others as well, we stock Hills which is also very good but I'm not going to try to persuade you to change, there's no need to. Royal Canin do one for the bladder as well , Hills isn't necessarily any better but we can't stock them all"
I think I previously mentioned that Morgan also gets cranberry tablets to help keep the ph of his urine down, Geoff the vet was very supportive and interested in our results.
I hope Sweep recovers quickly, check that the vet gives you enough painkillers when you pick him up. Morgan was very distressed for the first couple of days after his op.