I'm so sorry to hear that you have another blocked kitty. When you feed your cats canned food, do you also add some water to it? This is what I've been doing with my cats so that they'll get more moisture. I've heard that stress can also contribute to this problem. The most important thing to do is to make sure that he drinks plenty of water every day. This is why canned food is so important in a cats diet because many of them won't drink enough. I hope he won't have to have the PU surgery and that he'll be able to come home on Monday. I'll keep him in my thoughts and prayers.