I have a jade plant that started dropping leaves, and then branches. I thought it was because I wasn't watering it enough. I watered, letting it dry between watering. But then it got worse. Where some of the branches were falling off at the nodes it started to mold. After doing some research I cut it down to a stump and cleaned off the roots to check for rotting. they seem firm and healthy but I'm also not familiar with what rotting roots look like. I wonder why the plant would rot near the top and not in the roots. I need a second opinion. The inside of the plant where I cut it to a stump looks healthy as well (I think). I'm not sure where to go from there. What is the best kind of soil for a jade? What type and size of pot is best?

This is my current pot. It has rocks in the base for drainage, about half way up. You can see the parts of the plant as well, sick ones on the left and savable ones on the right.

This is what the current soils looks like.

This shows the rotting I found. The big one on the bottom right is the last piece I cut off to get to my stump.

The stump! Is this healthy or am I mistaken?
What is left of my beautiful plant. Roots and all.

Close ups of the roots. What are your opinions?