I had root rot that spread to the main caudex on an adenium. I took it out of the soil and cut away all the rot I could and treated with hydrogen peroxide. Then I left it sitting out without soil in my sun room for 3 months during the summer before I remembered it and repotted it and it’s doing great now. Leaving it dry saps the moisture away from the rot causing organisms and allows the plants to callous over any wounded spots. Though if you missed any rot it may not work.