Massive behavioural change in cat-thoughts?

Now some may know some may not I have three mogs, a tiny tortie lady who's getting on a bit and is very much the matriach catwise, and two toms-brothers, born here, neutered, who are coming up four this summer.
It's one of the boys, my big ginger Maxwell, who's behaving very oddly lately. I've had him too the vets a week or so after it happened and have had him back since, tests have been ran and he's been checked out and physically he's fine which bodes it's behavioural, but I don't reallly understand it.
He's lived here since born, with dogs and other animals, always been fine with the other cats etc. Yet about..nearly two months ago he started realllly viciously attacking the other two cats for no real reason, for example one would be sat there and he'd rush them and they'd end up in a big ball of hissing, spitting, clawing cat, most unpleasant. Then he took to being really "grouchy" with the dogs, more tolerable than with his feline friends, but lashing out just randomly for no reason. He's now started weeing in the house, pools of urine in the same particular places: under the dining table, in the hallway near the bottom of the step, in the bath, under the chair in my bed. And he wee's up, so I guess "sprays" the front door, the sofa..only one particular sofa though, and up bags of anything we may leave out.
Medically he's fine, the vet has given all clear twice. But it's really bizzare behaviour? And he was always such a loving chap before, he still is to people but is like a split personality with the other pets and his weird weeing habbits, and destruction..he ruins anything new in the house, and pulls the threads out of carpets/quilt covers etc, all very neurotic! All cats have free access to outside, so the vet wandered if it was a new cat locally moving in on Maxwell's patch and its stressed him a bit? I kept him in for a few days but we got cabin fever and got worse. I'm at a bit of a loss reallly, it may be just a phase so I thought i'd ask if anyone had any advice.

My initial thoughts when reading this, before I got to the last paragraph, were that something has suddenly changed which has freaked him out. Something such as a new cat on the block, this would cause him to stress out and mark his territory. I also wonder if something happened which maybe gave him a fright, at the point of fright his first sight was the other animals or even just the other cats, he may then associate the fright with them and lash out in their direction. It can be difficult to pin point the cause of the re-directed aggression. Can your vet put you in touch with a good behaviourist at all?

Hay
if it is a new cat moving in to his turf and it is stress would feliway (sp?) work?
ATD x

I'm unsure i'd opt for the behaviourist route due to previous negative experience, i'd rather sort it myself if i'm honest. I think i'll try a feliway plug in as hear nothing but good things about them!
As a side note all cats have bowls in different areas, beds in different areas, scratch posts etc, so all have plenty of space and "personal space" which I know can often be a major issue with a multi-cat household. It's just stumped me a bit!

Feliway will help alleviate some of the stress, no harm getting some but it can take up to a month for you to begin to see the results.
It's always better to find out the cause of the stress/upset in order to try to resolve the issues, and that may well be your biggest difficulty. Sometimes it helps to try to keep a diary, taking note of when these things happen, what was going on before it happened and after it happened. Did you notice anything such as a strange cat hanging round, was there any sudden noises. Be aware of anything that may have an effect on his behaviour. Once the cause has been pin pointed the next issue is how to deal with it so there is a resolve to the situation.

Yeah I had a negative experience too when dear Eva was still with us, so understand the reluctance there.
There are some very good books though and would highly recomend Twisted Whiskers by Pam Johnson.

Not really up on cat behaviour, but I'd agree with trying out a Feliway. When my moggie was alive we used one as she was seriously neurotic - used to pull out all her hair to the point where she was covered in bald patches. The Feliway really seemed to help chill her out a bit. I didn't use one all the time as they're not cheap, but it was useful when she started to over lick to calm it down a bit - break the cycle as it were.

Cats respond to T Touch massage the same way dogs do & a lot of the Cat Rescue people use it with semi feral-feral-unhandled-frightened cats. It couldn't hurt him

Joedee beat me to it it works brilliant with cats.

My first thoughts (having several of my own) was new cat in area, maybe imposed on his territory whilst you have been out
Gingers are fiery too, although Toms can be laid back, some Gingers can have a split personality when they become upset.
I have owned a few Ginger Toms, and I remember well 'one' who was so laid back he was super cool, until one night a stray call in
out of all my cats he was the one who reacted badly, and his behaviour went very much like your moggys, we had a terrible time with him. Unfortunately for the stray nature called his number up and our Ginger went back to his old former self.
Try finding where they do T Touch, you will be pleased I think with the results.

Thanks folks, I'll have a look into all what you've said. I may stalk him when he's out n see if I can spot any new cats etc. We live in a cul-de-sac and the existing feline residents are longstanding, Maxwell is quite the dominant male round here even over other toms due to his sheer size so I do wonder if theres somebody new in a different street or one from over the farm which is keeping him on his toes, hmnn in the meantime its just a pain in the bum!