Help with cat

Question
hi
 My mother in law passed away a month ago. She had a cat this cat has been around for 11 years and with alot of little dogs.
  Well My family has a very loving cat that has been around 2 big dogs.
 So I have been asked to see if the my mother inlaws cat can move in with me. My mother inlaws cat is a scared cat. An I am worried she is going to fight with my cat.
Help me please  

Answer
Sarah,

It's important to remember that cats are territorial and they don't tend to like change very much. The way that you introduce this cat to your household will ideally set the stage for the years ahead. Proper new cat introductions can sometimes determine whether your house will be peaceful or if there will be a constant power struggle between feline members of your family. I would recommend that you place the new kitty in a room by herself for 2-3 weeks (with all of the usual kitty amenities, of course) and several visits from human members of the household each day. The isolation period serves two purposes, it allows your resident cat to become gradually accustomed to the new addition and vice versa as well as protecting your resident cat from any possible viral or bacterial infections this kitty may have. I always recommend that a new kitty is checked over by a vet and tested for feline leukemia and FIV prior to being integrated into a household with resident cats. Feline leukemia and FIV are chronic viral infections similar to HIV/AIDS in people (don't worry though, they can't pass these infections on to people), they can be passed from cat to cat, don't worry though, they aren't transmissible to people. These viral infections aren't necessarily a death sentence for your cat, but it is useful to know the status of any new cat that you bring into your household because although these viral infections can remain asymptomatic for years they can sometimes be the cause of some serious health problems further down the line. The isolation period will cut down on or eliminate aggression from the new kitty and resident kitty as they will be able to smell and hear each other through a closed door. You can feed the resident cat and the new kitty on opposite sides of a closed door for the introduction period. Once the resident cat is trying to play with the new kitty under the door and are acting curious about her presence I would recommend letting them out and supervising the interactions between them very closely. I do think that it's wise to introduce your mother in law's cat to the bigger dogs separately from the cat because she may have more of a negative reaction to the dogs if they are excitable and pushy. It's probably a good idea to consider giving the resident cat and the new kitty a homeopathic remedy called Bach's Rescue Remedy which is a blend of flower essences designed to calm and reassure. Since the flower essences are preserved in a grape alcohol solution I would advise against trying to administer Rescue Remedy directly by mouth, instead you will want to add 5-7 drops of Rescue Remedy to a fresh bowl of water each morning. The cats will drink the water and get the Rescue Remedy that will help to ease them into this new situation and help to prevent any excessive aggression. Once the 2-3 week period of confinement is finished for the new kitty you can open the door and watch the interactions closely. If any of the cats respond with aggression I would suggest having a spray bottle handy to act as a deterrent. Never get in the middle of a cat fight as you can be seriously injured, use a broom to push the cats apart if necessary. If you would like further information on proper new cat/kitten introductions you can check out my previous answers on the subject. It's certainly best to try and remember that this cat has been through some significant trauma and change in the last while with the death of her caregiver so it's best to be patient and it's possible that you will see behavioral issues like acting clingy, excessive anxiety or even a lapse in potty training. It's very important to try and keep the cat's routines as close to normal as possible to try and prevent serious behavioral problems so I would recommend trying to find out what the cat was normally fed, how much she was fed, how many times a day she was fed and around what time she was fed as well as things like keeping her favorite toys, bed, litter box and brand of litter.