Muscle weakness

What kind of illness are we even talking about here?

We’re looking at a 68-year-old man here. It started out as just a slight dragging of his left leg whenever he got tired. Over the last seven years, things have steadily spiraled downward. His legs are losing strength—the left side is worse, and now the right is following suit. His arms are also losing power, again favoring the left, though the situation there isn't nearly as dire as it is with his legs.
He went from using one cane, then both, and now he's completely reliant on a wheelchair.
He’s seen plenty of neurologists, most of whom couldn't provide a single definitive diagnosis.

They checked his myelin levels—everything looked fine.
An MRI did show some narrowing in his cervical spine.
Initially, they didn't give it much thought; then, once they ran out of ideas, they pivoted to focus on that narrowing. Their working theory now is that he suffered a stroke in that specific section of the spinal cord.
However, nobody seems able to answer one simple question—usually, after a stroke, a person either recovers partially or stays exactly where they were immediately following the event.
In this case, we are witnessing a constant, visible degradation of his condition.

There is a mountain of medical records available to review, but for now, I can only offer this layman's summary.
If anyone has any insight into which direction we should be heading, we would appreciate it.

Look, I’m definitely not a doctor, and even if some MD decided to pop up in this thread, they probably wouldn't be able to do much without seeing the actual data, so you really ought to post your lab results so some professionals can see exactly what tests you've already cleared.
Honestly, everything you just described immediately made me think of https://www.mayoclinic.org/diseases-conditions/thyroid-disease/symptoms-causes/syc-20354264 but I guess the specialists have already ruled that out, right???

Has anyone else in their family dealt with something like this?

Out of all those progressive degenerative conditions, there's also this one: http://www.msd-manuals.com...cna-parapareza

Though, honestly, that doesn't really sound like what we're seeing.

Not a single person in my family has ever dealt with anything even remotely similar.
I’m going to upload the test results—it would be great if someone could advise me on which specific data points I should include.
ALS has been ruled out as a possibility.

Nathan White72 said:Not a single person in my family has ever dealt with anything even remotely similar.
I’m going to upload the test results—it would be great if someone could advise me on which specific data points I should include.
ALS has been ruled out as a possibility.

As promised, here are the medical reports. This whole thing started about 10 years ago.
The diagnosis is a brainstem stroke, but nobody seems able to explain why the condition is deteriorating so rapidly.