British Columbia: What's up with this windmill palm?

Hello all. Hoping to get some information on what is going on with my one windmill palm. I planted two of them in my backyard (south-facing) three years ago now. Same soil, same slope for drainage, same sun exposure, same fertilization etc....Every winter since they've been in the ground, I've boxed them up to protect from snow and cold snaps (I lost a few palms in the past due to harsh winters).

Over the last year or so, one palm has flourished and is looking great. The other one, not so much. Before this past winter, I cut several dead (or dying) fronds off of it and boxed it up. Having just recently unboxed it, all of the frond leaves are black and it just looks sad...Although, the fronds are very sturdy in the base and the base is well rooted in the ground seemingly. There are no new fronds coming up from the trunk however.

I really am at a loss here, as the other one is doing so well only 6 feet away. Pictures attached.

Any ideas or guesses?? Thanks!

 

"The other one, not so much" - there's an understatement!

I think it's safe to say that it is not the environmental conditions. I'd suspect a pathogen, then, though I am not very familiar with Windmill Palm Disease and which it might be.

 

Ok thanks for directing me to that link. I had a suspicion that it might have been a disease of some sort.

However, there are no remedy options to look at it with that link...not sure if I've missed the window now and its time to dig up and replace.