Mine goes dormant in the winter and looses its leaves. Since it's winter where you are, I wouldn't worry about the leaves turning yellow/brown and dropping off. As far as the stem getting slightly soft, My young Pachypodiums feel like this when they need water. Since the roots look good, and it's been dry for 3 weeks, I would try giving it a light watering and see if that helps.

Here's my horombense this spring, just starting to break dormancy...

and here it is now...

That is a magnificent plant! Well done to you.

How long did it take you roughly from the size of my plant to branching and growing that awesome caudex?

Also, the one i have has really long leaves but yours show more rounded ones. I wonder if it's to do with sunlight or overfertilising (i do it 1-2 times during spring and autumn).

Thanks for sharing your experience.

Sorry, another question, stupidlazydog... did you prune it to make it multi-branching?

I wish I could take credit for it, but my husband bought it for me as a birthday gift last year. My pachypodiums branch on their own, I don't prune them. They often seem to branch after flowering.

The leaves on your horombense actually look just like the leaves on my young P. rosulatum. The leaves on my horombense also feel a bit fuzzy on the reverse side.

Hmm... I just googled rosulatum and you're right, there's more semblance here than the P. horombense name it was sold under. There's no fuzz on the underside either.

Oh well, as the saying (sort of) goes: a pachypodium by any other name... :)