Urinary Problems- is our vet looking after our cat,?

Hi, I am looking for some advice with regard to our 4 year old male cat Rocky. On Tuesday of last week he was squatting all over the house and was peeing very small amounts at a time whilst crying. We took him straight to the vet who expressed his bladder and gave us some anti-inflammatories and Royal Canin Urinary diet. The vet told us it was most likely stones and we had to be very careful as his bladder could explode. We took him home and spent a sleepless night caring for him. We then had to go back to the vet the following day as he still wasn't peeing properly and was now refusing to eat. He again had his bladder expressed and was given a stress reliever and a muscle relaxant- we were then told that this issue was multi factorial and they couldn't be sure what was causing the blockage.(Although having read tonnes of forums we believe it is due to having a high grain wet & dry food diet as we now know he had struvite stones and the crystals in his urine have reduced since having the urinary food). We then booked Rocky in for a catheter fitting on the Thursday- ,we brought him home afterwards with more tablets- an anti-biotic this time and he was given pain killers via injection. The following evening we went for the catheter removing and were told it was crystals that had caused the build up but that he had been flushed and we should see some improvement in his behaviour and peeing again. Saturday and Sunday he seemed to pee normally- only small amounts but something at least. Then on Monday he stopped peeing all together but he was leaking small amounts throughout the day. Also,he did have a dry and painful bowel movement- we took him back to the vet who told us his bladder was full and he needed to be expressed again (he had just eaten and had a full tummy). She took him into the back to express him (she said she injected into the bladder to take some pressure off before squeezing the bladder manually to empty it.) She sent us away with some cystitis tablet to add to Rocky's pile and some oral pain killers to be given every 8 hours. She said that he was so full that his bladder could have exploded!
Today Rocky is not using his litter tray to pee in (he has rolled around in it and has played with his toys in it), he is leaking urine constantly and is grooming the area non-stop. When I rang the vet surgery they said not to worry unless he was trying to pee but can't (he isn't even trying to pee!)
We are so uncertain as each time we have been to the vet practice we have seen a different vet (they are a multi-partner surgery) and they all give contradicting advice.
Rocky in himself is an amazing little dude who is still very playful, he is not drinking at all but is eating all of his urinary food twice daily. He isn't hiding away as he normally does when he is ill and he hasn't made the heartbreaking cries whilst using the toilet since Saturday (he did when having a BM yesterday though) and he didn't fight us when trying to get him in his carrier for the vet. Are we just kidding ourselves? Clutching at straws?
We love this little guy a ridiculous amount- he really is our baby and I am very frustrated that no-one has given us clear advice. He is acting so normally- he wants to go out into the garden and wants to play and cuddles but then he gets frustrated with the leaking and starts grooming again
Has anyone experienced this issue? Should he be leaking? Why isn't he even attempting to pee- Could it be the medication
Any advice would be greatly appreciated as my Fiancé and I have had a stressful and fraught week and have spent a small fortune but we are not even sure if there is any hope or if we are just prolonging his suffering?
Thank you in advance for any replies- we would be so grateful [emoji]128522[/emoji]

How long has he been on antibiotics for? Did your vet do a urinalysis? Did he have crystals and a high pH? What are you feeding now? Yes, high grain foods cause UTIs, but also so does kibble. Ideally, cats with a history of urinary issues should be on an all wet food diet to help keep them as hydrated as possible. 

Yeah they said it was struvite crystals from alkalinity in his bladder and he was eating a lot of dry food so he's completely off dry food now and onto Urinary food for the past week. He hasn't had dry food at all since Saturday- much to his disgust. Rocky has been on antibiotics since Saturday (today is the 4th day.)
As I said he seems better in himself I'm just worried about his leaking, not drinking and not using the litter tray but the vet seems to think this is normal.
Thank you missmimz

Is it possible he is leaking urine due to the catheter and muscle relaxers (better for him) or could it be because his urethra is traumatised or is it because his bladder is so full the pressure is forcing urine out (worse scenario).

You should get your vet to teach you how the bladder feels when full compared to when it is empty.  Whichever condition it is in the next time you see a vet, have them teach you.  One of my very first cats blocked (this was in the 1960s) and since his bladder had been so stretched out before I got him to the vet, after he was unblocked and was recovering, he had a tendency to only empty part of his bladder when he used the litter box.  The vet taught me to feel the bladder when it was empty and then when it was full and then when it was partly full and taught me to express the excess urine after the cat had used the litter box so his bladder would be completely empty.  I did that in the bathtub, just pressing in the way the vet had taught me, until the excess as pressed out.  Pretty soon he was emptying his whole bladder by himself and he never had a recurrence of the blockage.  I fed him only wet food after that. 

If you say your cat does not seem to be drinking much, it's because he is on wet food now.  He gets his hydration in the food.  In fact, you should add a little liquid to it to increase the hydration and flush out the bladder.  Boil up a chicken in a crock pot and use the broth to add to his wet food.  It will make it taste better and he will get even more fluid with each meal.

Thank you very much Red Top Reduce, we really appreciate your reply. I will ask the vet to show us and will try the chicken broth tip- thank you very much.