New Cat/Old Cat

Question
QUESTION: My friend and I have recently moved into an apartment together where she had a cat who is about 2-3 years old.  I went to our local humane society and got a 6 month kitten.  Today her mom broght back her old cat Baxter whom has been living with her for about 3 months.  The story is when she lived by herself she would let him out during the day and let him roam about the neighborhood.  She would let him back in when she got home from work.  He started then hissing, biting and growling at her.  So she took him to her mom's house to see if that would help since he would be able to be outside all he wants.  He then started to get depressed, wouldn't eat, and just wanted in the house at all times.  When we went to greet him today he did the same old thing he hissed and growled at us and when she went to pick him to take him outside he scratched and bit her all over her arm.  He basically doesn't like her anymore and she doesn't know why.  So my question is how do we rehabilitate him to be a nice and loving cat like he used to be and to teach him to get along with the other two cats here.  

Thanks so much
Amanda

ANSWER: Hi Amanda,

Let me just get this straight--in your apartment you have a 2-3 year old cat and a 6 month old kitten and Baxter, who is how old?  Had Baxter been living with the 2-3 year old cat or is this one new to your friend also?  What are their sexes and are they all spayed and neutered?
Depending on his age the hissing, growling and biting would indicate sexual aggression (if he's not neutered) which may be intensified by the presence of the other cats.  If they are also not fixed that's something you can do and it would go a long way to helping the situation.  If Baxter is a very old cat his behavior could indicate a medical condition such as blindness or pain somewhere.  If he is an old guy you should have a vet check him out.  Is it possible he doesn't want to go outside any more and is there any reason that he couldn't stay inside during the day?
You can get a calming liquid to put in their water, something like "Rescue Remedy" and also a plug in pheromone emitter like "Comfort Zone" (if your local pet store doesn't have them you can try on line; I know drfosterandsmith.com has both) to help relax him.  Give him as much attention as you give the others but don't try to pick him up if he doesn't want you to.  Watch his body language and back off if it looks like he's getting upset.  Once he feels like he's back in control and more secure with staying in one place he'll probably return to normal.

---------- FOLLOW-UP ----------

QUESTION: Thank you and yes they are all males, all fixed and Baxter is about 8-10 years old.  She had the other cat since he was a kitten and they have both lived together with her.  Since we now have a screened in porch, he will most likely be out there most of the time, he loves it there.  He lays in the sun and sleeps, it's too cute!  He's always been a loner cat, likes to be by himself.  I will definately talk with her about taking him to the vet to get a check up and too look for that Rescue Remedy to see if that helps.  He will get as much love from us if he will let us.  Thanks so much!

Answer
Hi Amanda,

Eight to ten years old isn't terribly old but he may be slowing down a bit and the new kitten might be irritating him.  Just let him do his own thing (still get him checked by the vet, though) and you may be surprised to look down one day while watching TV to find him sitting on your lap!  I like the older cats, they can be grumpy but they're pretty predictable in their grumpiness and can be quite sweet in their own way.