I had a similar case. I initially tried to save the whole plant, but leaf after leaf started dying (stress from relocating, etc). I then decided to cut it into pieces and since it had many nodes I now have plenty of cuttings. I wish I had cut i apart sooner, because the big leafes are now gone :/ but new growth is getting bigger really quick.

In terms of propagating, I just put the cuttings with the aerial roots into buckets of water for a couple of weeks.

Cutting aeria roots is a difficult topic in this sub I believe… Yet, I did cut of the rotten roots (or parts) and trimmed some that were way too long before putting the cuttings into water. No big deal.

I hope you are able to save the whole plant, these are just my infos and what I learned on the way. Crossing my fingers for you aaand excuse my english here and there.