We found a cat, a Persian on the streets a few years ago and took him in, he was at deaths door and we nursed him back to health.

He was an 8 year old tom and the vet and everyone kept saying, oh no you cant have an un-neutered tom in your flat, especially as he has to be an indoor cat. He had to become indoor as he got cat Lukemia whilst on the streets so no immune system, so no more contact with the outdoors and other ferral cats. We did have a decent sized balcony he would sit on for hours.
I kept saying, well he hasnīt sprayed yet, he must like us! They kept saying its because he is ill, maybe when he gets better he will start spraying. They were right! He sprayed inside OHs expensive motor bike helmet, threw that away, then his jeans. I still said no to neutering an 8 year old, I though that was mean.
The day he sprayed on a pile of my clothes was the last day he had his bits!

Whisked him off to the vets the next morning! When he came home, he tried to jump up on a chair that first night and fell back down again, ouch that must have hurt. The next day he was absoultely fine and stopped that awful yowling at night as well. Never looked back, had a loving cat for nearly 3 years until the Lukemia caught up with him.