Q.Grandmother’s Jade Plant sick
Help! A large Jade plant that I inherited from my grandmother is in trouble, and despite researching various websites, I’ve been unable to find out what exactly is wrong with it. The plant is currently potted in a terra cotta pot with CS potting mix. I’ve been watering it once a week since it’s currently in a growth cycle with a lot of new shoots. However, there is one branch that is currently shriveling upon itself and the new growth at the top of it is failing. This shriveling of the stem/branch starts at the base of where the leaves currently exist and spreads up and down the branch until the branch itself falls off.
Originally, the Jade plant was in a pot too small for it and its roots were bound. It was so top heavy that you couldn’t hardly touch it without fear of the dang thing toppling over. My mother had been overwatering it and its leaves had started to turn brown. I repotted it into a slightly larger pot with sandy soil for added stability and drainage. Later, this current issue arose, I repotted it again this time with CS soil and trimmed back the bound root ball, which was firm as far as I could tell.
While there is a lot of new growth on the plant in places where branches have fallen off, there is still some sort of horrible sickness in the plant. In the last few days, in addition to the shriveling branch, there are also large brown dimples appearing! What is going on? This condition is unlike most of the common ailments I see for Jade plants.

It sounds as though your jade has some type of rot. You should avoid watering your jade on a schedule (you mentioned watering it once a week) and only water it when the soil is just dry to the touch. Rot develops if the soil is over-watered and sometimes plants do not fully recover from it. I am suspecting that your jade is afflicted with bacterial soft rot for which there is no effective treatment and might be why the problem with your jade has not resolved itself. More information on bacterial soft rot can be found here:
https://www.gardeningknowhow.com/plant-problems/disease/bacterial-soft-rot.htm.
For a refresher on jade care, please visit the following link:
https://www.gardeningknowhow.com/houseplants/jade-plant/jade-plant-care.htm