Still Peeing In Bed!

Question
Thanks for your input a week or so ago on this topic. Here's an update and followup question or two: After waking up to cat pee in our bed a couple of times recently, we took all three of our cats to the vet who checked each for bladder infection but didn't find any. Instead, we discovered the oldest of our cats now has a significant amount of blood in her urine as her kidneys are apparently failing. Our hypothesis, then, is that she may be leaking small amounts of urine (containing blood and whatever else) which is unduely encouraging the dominant male cat in our household to place his significant mark over. Does that sound like a reasonable theory for the sudden peeing in bed? Or do you think we should be looking elsewhere? We don't think any of our cats is purposely acting badly but something strange is going on. For the moment, we've isolated the dominant male in one part of our condo, away from the ailing female and master bedroom to see if that reveals anything new (and to emphasize to him that peeing in our bed is not acceptable). While I'm not totally convinced he's doing most/all of the peeing, it's likely he is from what we've actually seen (since we've been asleep when most of the peeing in bed occurred). My wife and I, married now about a year and a half, only merged our cats--two of which were mine (including the dominant male) while the ailing 13-year-old female was hers--temporarily in her condo (while we plan for a house) about 15 months ago, and while they haven't become the best of friends they have lived somewhat amicably for a good part of that time. Also, while the male used to be an indoor/outdoor cat, since moving to my wife's condo, he's been confined indoors. Any insights you can provide on how we can improve our present situation (and possibly solve this problem) would be greatly appreciated. Thanks!

Answer
Did the vet give the older cat any medication?  And yes, it's reasonable to believe that the male cat is reacting to the female's illness.  Any change in a cats life will cause him/her to behave differently.  I am thinking that you need to keep the male out of your bedroom until the problem is no longer a problem for him.  He is probably not acting out purposely, but merely following an instinct to mark his territory.  Good luck, and I hope somehow you can help the female with her kidney problem.  

Barb