I think a friend may be worth a go. It may be hard to extinguish his desire in going out completely as some cats just cant do without the great outdoors (even though they dont generally go far anyway) cant the courtyard access be limited (possibley supervised) to day time?
Does the flat have a balcony? Take a look at the ideas on this page for a Catio. I also recommend in taking a look at the Catification Page for making indoor spaces like a cat heaven (some look quite sleek so keeps your house modern looking too, if thats your style)
http://jacksongalaxy.com/2012/07/03/catification-aslans-custom-catio/I also second "Tiggy's Mum" about the toys! the Da Bird is amazing!!
I havent personally converted outdoor/indoor cats to indoor only but do look into ideas on that page...although American, in the USA cats are predominantly indoor animals and the Cat Daddy is amazing!
You may find he cries even more at first as everything will be new and out of his comfort zone - he'll just be needing some extra TLC. Cats only cry to communicate with humans. As a breed they dont normally meow at each other to communicate so the lads just chatting to you lol .....although some are much louder than others!! My old fella went deaf and i could probably have heard him from 5mile away, up wind
I've never had to use a spray or even know of it being used
I think care has to be taken on what the purpose of use is for. To prevent/discourage a bad behaviour or just reprimanding their need for grub
But like i say, i've never used one, so am just presuming its purpose
- me and the OH just take blurry eyed trips to fill bellys, watch them - cos we know any foollish thoughts of going back upstairs too soon, will mean we have to go back to let cats out, cats in.....
well i say ME and the OH
its usually just my OH cos he's a lighter sleeper than me
i hope you get some brill ideas for keeping indoor kitty happy
Let us know how it goes and whether it was easy or not