18 years is a good long life for a feline friend, I'm sorry you are facing such difficult health issues. We put our Sis down this Spring, 17 year old, not easy. She had lost weight, didn't like to eat and spent more days limping around and hiding then cuddling. I knew no matter what we did for her, the quality of her life wouldn't really be improved, just prolonged. Nobody wants to walk our friends to the cusp of the rainbow bridge, but sometimes it must be considered. I just couldn't poke, prod and push pills down her throat anymore. She hated it
 I hope you both find freedom from sufferinghttp://www.peteducation.com/article.cfm?c=1+2118&aid=224 4951