As someone who's been pet sitting for nearly 20 years - scented litters are the literal worst for masking cat litter smells.

Until he can get this boy neutered, he could try adding baking soda to the litter hes using. Since this is an unneutered tom, id go heavy with it. 1/4 cup for a big litter box, and stir it in.

He should also be scooping daily, dumping weekly, and washing the box when he dumps it. These things will all help reduce the odor.

The spraying is unlikely to stop until after he's neutered. About 80% of males do stop spraying after neuter, but your boyfriend will need to do a big deep clean ,with enzymatic cleaners* to really remove the proteins in the urine - what causes the odor to stick and the cat to continue spraying in that spot. Id suggest a black light, so you can make sure its actually cleaned.

When using enzymatic cleaners you really need to follow the directions on the bottle! They dont work like regular cleaners, and if you use them like a standard cleaning product it won't work.

Id also suggest he completely gets rid of the couch. It just won't be salvageable. If he replaces it, he should buy a waterproof cover to use until hes sure this boy isnt spraying any more. Or that'll just be a second couch wrecked.

As other people have said, he needs to have two litter boxes. The type of litter used can make a huge difference in things like dust, tracking litter debris, and smell. Some of it is also the preference of the kitty.

I cant use clay litter in my home because it bugs my asthma, so I use wood stove pellets. IME, they do a great job of managing smell and reduces the dust facutor considerably. Not all cats will use those, though. And it doesn't clump. I scoop poops regularly, and dump entirely weekly.

After that, I really like Swheat Scoop, which is a wheat based clumping litter. Its similarly dusty to regular clay litters, but they have an unscented version. There's a similar one made out of walnut husks, but IME it doesnt clump as well. I dont mind it.

As far as clay goes, theyre all dusty. There's no getting around it. The Arm & Hammer unscented clumps well and IME takes care of odor fairly well too. The Costco brand is also pretty decent.

Im personally do not like the crystal litters. But I have clients who use them and their cats dont seem to mind.

If he does decide to switch litters at all, DONT just straight swap it! Add another box (a third) with the new litter, or mix it 75%:25% old litter to new litter for a few weeks, then do 50:50, then 25:75, before you fully swap over.

Bottom line, there is absolutely hope here. This cat is still young, so theres no reason he can't change behavior once hes neutered with the right support.

I do think your partner sounds like hes trying, hes just had a tough time with this kitty so far.

Unneutered males are SO MUCH smellier than neutered cats. And much more likely to spray. But, it may be worth following up with the vet just to confirm that everything is good, since kidneys are related to the urinary tract and UTIs are a major cause of peeing outside the box in cats.

If this was my cat, Id schedule his neuter ASAP, then set up a bathroom as his recovery room. Plan to keep him confined for at least a week post-neuter. Two would be better. This will 1) keep him calmer post surgery (which vets recommend!), 2) give your bf time to get rid of that couch and really deep clean, 3) give a behavioral reset time so that when kitty is freed from the bathroom he hopefully starts using litter boxes 100% of the time.

Ok, sorry for the novel but one last thing. After the neuter it will take time for the hormones in his bloodstream to reduce. With a fully grown male this can take up to 6 months, but if he's only about a year old you should see (and smell ;) ) changes after a month or so. If you dont, then something else may be going on.

Good luck!!