Hey there, that also breaks my heart you had to rehome him also. I have 4 cats in addition to my 3 dogs. I have had cats all of my life (39yrs) and only once did I run into a serious problem like this. However I would like to share that in addition to the enzyme treatment that I run through my carpet cleaning machine I also use a product called Bio41 and I throughly spray carpet and/or fabrics after. I bought it at a local cleaning supplier. It removes absolutely any trace of scent. I love it! If you can't find it locally you can buy it from the company online
www.bioenviornmentalsystems.com It works well so that dogs and puppies can't smell where they've urinated.