I think that battle is over buddy. The stem is fairly necrotic looking. If I were you I would take some cuttings just incase she does die off. Absolutely gutted for you, she is amazing looking 
You might be lucky if those two nodes beneath the damage survive you might be able to salvage her.
Oh my, that is Maui wowee from here, glad I have one more. Is there anything I can do to make sure it doesn’t happen to my other ones?
Not sure, have a look on here for mould control measures, there is talk of altering the pH of the mould site. That stops the mould from spreading but you would need to search for the answers on here as I’m not sure
Thank you for your help I will look around
Just be careful how you handle that mould. It doesn’t take much to disturb it and you don’t want it flying around the place 
So we let it grow and it looks like the center stalk is dying and the other stalks are growing. Should we cut the center stalk out and let the outer ones to keep growing? Or should we cut it down?
My heart goes out to you… 
hate that crap.
Sorry for the late reply. I had no idea you had replied. Top part of the plant looks like she is going to die. As suspected the bottom part is doing ok. Take cuttings quickly before it’s too late. If you want one of us to drop by then put @ in front of our user name, that raises a flag and let’s us know you’re looking for a response @horsetrack1
Once you’ve taken cuttings and its definitely deteriorating then cut the top part and leave the bottom to grow out.
Powder sulfur brushed on the stem with a paintbrush prevents stem rot. It’s a must when growing out doors, the only thing you can do this late in the game (not really) is spray the infection with hydrogen peroxide or deluded bleach.
But honestly—
"Taps" performed in Arlington National Cemetery (summer and winter) - YouTube
Can’t you put peroxide into the water will that help🤓? I’m in a humid place and had that happen on some hefty size plants. So will do the powder then and when do you recommend?
I stood for a moment of silence:sneezing_face:
We all feel your pain 
Hydrogen peroxide (H202) helps in more ways than one!
It kills fungus nats and their eggs.
Stops the formation of hydrogen sulfide (swamp water smell).
Helps slow nutrient binding and precipitation.
Supplies oxygen directly to the roots.
Helps prevent anaerobic bacteria.
Thanks I didn’t know that. We cut her down was scare the mold would be in the plant and didn’t want to take that chance.
Do you put the sulfur on in the beginning or when you see a problem
@horsetrack1 Sulfur is preemptive, and you don’t have to worry about sulfur toxicity, it needs microbes to break it down before it’s available to the plant. Anytime conditions can incubate stem rot, the sulfur will stop it.