Final update for now, I've repotted my plant in cactus mix, a very well draining type of soil composed of sand and peat. I'm hoping this is what my plant needs to get back to health. I'll post an update in about a month, as requested by JP. Thanks all for giving advice and information, I really appreciate it!
Final few pics:
The cigar leaf looks to be in a bit worse condition than yesterday. I really, really hope it will unfurl over the next few weeks and makes room for a new one!