Try feliway plug ins to help her be less stressed first. Next try cat introduction methods to help her learn to tolerate the dog and hopefully start to get her to associate the dog with reward. Meaning try your best to keep them separated (i know it will be difficult in the small space) and reward them both when they r around eachother. Have their mealtimes at the same time and have one in the bathroom with the door closed and the other in the other room while they eat. Sleply move the bowls closer every meal and eventually open the door and then just have them eat together. Do this process slowly. Look on youtube for jackson galaxys on introduction. I know you said kitty is not receptive to pets right now but are you still trying to spend time with her? Jist being with her and trying to play with her and give her interactive treats like churu or cat lolly pops will help her get out of this depression. What does she enjoy doing? Does she like wand toys or looking out of the window?does she like being high up? Try to enrich your current environment for her. If she enjoys looking out of the window set up an area the dog cant reach thats just for her. Like a window rest or a cat tree in front of the window. If she likes interactive play make sure you give her private play time in a room with the door closed so the dog cant stress her out during her one on one time. You can also find other cat furniture to give her space high up that isnt in front of the window too. Amazon and chewy have good affordable cat furniture options. Look into something floor to ceiling if she likes climbing. https://a.co/d/02QVWcDE Heres a cheap one i personally have and my cats love it. Theres other cheap options too. If she likes being in enclosed spaces they make ones with cubbies they can go in. So basically just try to give her alone time with you guys and try to cheat her up. Cats get depressed too. You can make your space bigger for her by getting her stuff she can climb up away from the dog and have her alone time to decompress. And also attempt to make them like eachother more with the introduction method. Good luck please take care of her. Remember shes a senior and her happiness is very important and that she loves u guys, you are her family. Shes getting old but still needs to play and get play time to make her healthy to live a long life.
