Oh, wow, what a plant story! TY for sharing it. Sending good vibes for recovery! It does look like it will pull through.
Have you considered moving this to a pot? It's so common for these to decline in water after right about the same amount of time as you mentioned for yours, 5-6 years. So many similar anecdotes that I've read over the years.
This is a variegated one, had for 3-4 years. This summer, it decided to make new growth from the roots.
