Litter mates not getting along....

This might be a long winded story so I apologize now. I want to try and get everything right. My wife and I have Domestic Shorthair ("Eddie" and "Cosmo") cats about 3 1/2 years old. They are both male and are litter mates. Just for the record, Cosmo is by far "Mr. Dominant" Anyway. This past week Eddie spent three nights in the hospital for Chronic Renal Failure. He is doing fine and it was caught in the early statges and all of his levels are back to normal, for now. Eddie went to the hospital on Monday morning and we picked him up on Thursday evening. When we returned home, we put the carrier in the living room and opened the door. Eddie walked out and began hisusual sniffing and investigating. His brother, Cosmo came running down the stairs to greet his brother, took a couple of sniffs and out came the hisses and growls.

We were told that this is somewhat normal because Eddie has a lot of new smells on him form the hospital. They will get over it. As of today, Saturday afternoon, we have made some progress but very little. We are unable to leave them together unsupervised. Cosmo has attacked twice. No injuries just the hiss, swat and "scream" Eddie has been a real trooper, just runs away.

There has been some progress. Cosmo will get close enough to sniff and has even done a little licking. They also eat within 1 foot of each other without any issues. The biggest concern we have is that Eddie is doing his best to stay away but Cosmo insists on stalking his brother. He shows a decent amount of aggression by following Eddie with the hissing and growling. I wouldn't be so concerned if they both kept to themselves but Cosmo follows Eddie around....and harassing him. We keep them separated when we are not home and we slept with them in seperate rooms last nigh because we felt that the both of them could use a good, stress free night of sleep. It seems if Cosmo approaches and Eddie is still, all is good. If eye contact is made, not so good.

We have tried a few things so far. We have brushed Cosmo and then brushed Eddie with the same brush. We have pet and rubbed Cosmo and then rub and pet Eddie right away with some of Cosmos hair. We have taken a damp towel and tried to "wash" some of Eddies foreign smells off him. Most important, we have tried to let them be and sort this out themselves.

My fear is of course injuries. Will Cosmo injure or kill his litter mate? IS he that angry?

The Doctor told us that this should pass and just to keep a close eye on the both of them. Another Doctor told us that they may never get over this and should consider having them live separate lives if Cosmo can't readjust.

Im sure I left some important stuff out but I'm basically looking for some advise or tips. Has anyone else been through this? Some stories to share? HELP !!!

Some ideas:

Put some pure vanilla extract under the chins of both cats and near their tails so they begin to smell alike.

Consider a Feliway diffuser in a couple of the rooms where they will be together. It is expensive but tends to reduce some of the hostilities.

Review some of the techniques of introducing two new cats together. Keep them separated but feed them on either side of the door. When they are together, distract them with play and treats.

Its the smell, it takes a while for them to smell alike again. It took us about a week. Thats why it took the cats a while to get use to the wee one.

I would suggest doing the vanilla technique described above, and separating them for a few days. Keep an eye on them, and when they start paw-playing under the door, test them being around each other by opening the door. Keep this up, and within about a week, your boys should be best friends again.

Let us know how it goes, and be sure to read the various articles on this site about introducing cats, which is what you're basically having to do.