My wife and I have this lilly, at least she tells me it's a lilly,
that is in really bad shape. Every couple of weeks it gets a new
healthy looking green leaf. Within a few days, however, this new leaf
starts to get a dark, limp area on one edge, that spreads over the
next couple of days until it is a withered mess.

The entire plant has only one reasonable leaf on it, and that one is
on its way out. What is wrong with this plant?

Thanks, Mike