Bringing in a six year old cat when there are two at home one twelve one six

We have two cats at home that have been together for six years.the twelve year old is cosmo he is not.the most personal cat around but he is very loving to my wife and myself.he tolerates my grandson my daughter and son.he also tolerates the six year old cat newman. My son just moved back in after his marriage end ed he brought his cat six year old remy he gets along with everyone but the other two cats. We have to keep him locked in my sons room because whenever we let him out he goes after the other two cats. We don't want to keep him locked up but we don't know what to do we want to keep all three if possible. Any suggestions would be greatly appreciated.

RESPONSE:

Remy is scared. His world has been turned completely upside down and he is having a hard time coping with the changes. Walnut Bach Flower Essence may help him cope with the changes. This behavior is quite normal and should calm over time but the longer you keep him seperated from the other cats, the longer it will take. Make sure there are plenty of high up places and cubbies for the cats to hide in and get away from each other. Play with them often to help Remy burn of his anxious energy and help the others feel more confident. Give them treats when they are together in the same room. This helps them all to associate good things with each other. Make sure they are fed in seperate areas so they don't feel there is competion for food. Because they are all adults, it will take some time before they will learn to tolerate each other. Just stick to a routine, offer play and treats, and don't react when they confront each other. If you get upset, it will create more anxiety in the house which will in turn make the cats more anxious and more inclined to try to bully each other.
Good Luck!

Donna, House Full Cats Mom