I'd remove the bad leaves and spray the plant with Listerine...not the minty stuff
Are the bad leaves only on the softer canes? If so, it reminds me of a huge plant I saved...take it out of the pot, remove the soft canes altogether and spray the root area well with the Listerine, then repot into fresh media. I thought my plant was a goner but I was able to get it back on track and now it's thriving!
Here's the story:
Baffled!
and here's the plant today
