Q.christmas cactus , the branches are falling off . the plant is still alive.the plant is 5 or 6 yrs old.
i have other christmas cactus that are the same age , but are not dropping branches?

Most holiday cactus issues are due to moisture problems, too much direct sunlight or cold drafts. During winter when the plant isn't actively growing, it requires less water. On the other hand if the air in your home is very dry, the plant loses moisture at a higher rate. Using regular potting mix makes getting the moisture right more difficult. It stays too moist for too long and roots start to rot. It often helps to add coarse sand or extra perlite to the potting mix to speed drainage and drying. See if this article helps: https://www.gardeningknowhow.com/ornamental/cacti-succulents/christmas-cactus/limp-christmas-cactus.htm