Stress in a Cat's Life

One of my cats has matted fur. I haven't been brushing her for the last 2 months due to plumbing problems in my place so I have been living from one friend's to another and I go back every other day to clean their litter, feed them, spend a bit of time until nature calls. What can I do or give her to take?
My other cat loves to clean herself and is now furless at the front of her to her legs. If I pat her, afterward, she goes and clean herself. A few years ago, I took her to the vet, they said she is bored and gave her medication. I gave her the first one but she looked like there was no life in her so I threw it out. She also tries to clean the other cat. They have both gone through alot over the past 6 years with me being in and out of the house and various moves. They are approx. 15 yrs old. I want to make their lives better for them... what can I do?

It does indeed sound like both you and your cats have been through a lot in the past number of years. I hope all will be sorted out with your plumbing soon so you can all live together again and get back onto a routine. Routine is vitally important in a cat's life; they do not care for change and each disruption may be seen as a stressor in their lives. Flower remedies may be helpful here. Available at most good health food shops, look for Walnut, Crab Apple, Elm and Honeysuckle. In a 50 ml glass dropper bottle add 2 drops of each of these flower essences into 50 ml of spring water. Put one dropper of this mixture into the cats' food twice a day.
Second: your description of your cat's obsessive licking may be due to a food allergy. Please see the work of Richard Pitcairn, "Natural Health for Dogs and Cats", "The Complete Herbal Handbook for the Dog and Cat" and "Cats Naturally" by Juliette de Bairacli Levy and "The Barf Diet" by Ian Billinghurst for further information and recipes.