MeowWiki has rescued 23 cats from extremely sad situations. We are big advocates of rescue and adoption, as well as keeping our cats indoors, so they have a healthier, happier life. Some of our rescues have suffered horrible injuries with life on the streets, and we've taken feral male cats who were not fixed and integrated them into our home with great success. Anything can be done when you have patience and love with a slow integration and separate areas/rooms and short visiting hours to start and build that up over time.
We share some of the very conditions we've experienced and had them treated by experienced veterinarians. Some of our cats have lived to 19-20 years. Cats usually show no symptoms when it comes to lymphoma and blockages until it's too late. So please watch for any slightly different behavior--even in voice (meow) and weight change--because it means something, along with frequent vomiting or hiding. Wishing you the best, longest relationship with your cat(s) for years to come!