My dad died 2 years ago of this rare, fatal disease. I can't stop thinking about this moment.

I will never forget the moment my dad's eyes danced with recognition. One of the last times his bright blue eyes met mine and meant it.

The sun poured in that gorgeous spring day in 2022 and pierced the dozen windows of our living room. It lit up the light green walls, too, and illuminated the bright teal kitchen backsplash. Woodpeckers pecked the gray siding outside, birds chirped within earshot of every bedroom. A tire swing – long unused – hung in the side yard. If I listened closely, I could hear a younger version of myself asking Dad to push me harder. Faster.

The living room TV stared back at us. Blank. The news was usually on in the morning at this hour if someone was home. Dad was never here at this time on a weekday. But everything changed when he started showing symptoms of aphasia – yes, like Bruce Willis – that turned out to be the one-in-a-million, always-fatal neurodegenerative condition known as Creutzfeldt-Jakob Disease (CJD).

He died weeks later.

"Dad, why don’t we go through the worksheet?" I urged. Like I used to when I was a kid and needed help with math homework. My 8th grade math "problem of the week" became our problem of the week.

But this time the worksheet wasn't mine. It was his. Homework from his speech pathologist. His aphasia kept getting worse, not better. He started forgetting things too quickly. The physician he once was became a too-distant memory.

Dad, do you remember your name?

"Hey Dad, what’s your name?"

“Mark,” he said. Right. Good.

“That’s right! What about my name?”

“Mark.” He said it like he was trying to say "David," but was defeated. No one prepares you for when your parent looks at you and can't remember the name that they chose. I had first experienced this a few days earlier during another beautiful spring day, on a walk through a park near my childhood home. I asked him my name after a trip around the large pond, after being warned he might not remember. I didn't look at my reflection in the pool. I couldn't bear the horror that would reflect back at me.

“No, I’m David," I stammered. "What about your wife’s name?”

“Mark.” No. Again. Lisie. Her name is Lisie. Your wife of almost 31 years.

“No. What color is this folder?” I asked, frustrated.

“Red.”

“Yes!” My blue eyes lit up like wave pools and met his. He looked at me, but almost through me. Not totally registering my presence but not missing it, either. Like he was stuck between worlds.

The speech pathologist gave us this "red" trick. For whatever reason − one I’ll research another time − asking him the color of this red folder grounds him. Brings him down to earth from wherever his mind is at this point.

Maybe he’ll get better, I thought, every time he gets this right. But then I asked him to name objects around the house – a remote, a blanket – and we’re back at square one. Repeating the name “Mark,” or the color “red.”

His favorite song

“Dad, why don’t we listen to some music? Maybe ‘Take Five?’” He shrugged. I'm not sure whether he heard my question but either way it gave us both a break.

"Take Five," by Paul Desmond, is his favorite song. A jazz staple. I scrolled to my Spotify app and started playing it.

The drum beats began. Then the saxophone swung in, the star of the show. Dad played professional jazz in the Catskill Mountains of New York many years prior and wouldn't let anyone forget it. He played the clarinet, too, in a trio with a flutist and violinist, for decades. He often pulled out either or both instruments for family gatherings like Passover, for informal recitals. These memories swarmed my mind, musical notes leaping around like the plague of frogs.

“Da-da-da-duh-dah-“

Wait.

He was … singing along? The same man who can't say my name, my mom's name, sometimes not his own name, knew the tune of "Take Five?"

He wasn't smiling. But he was singing. Somewhere, in the recesses of his brain that the CJD prion proteins were destroying, he remembered. Remembered playing "Let My People Go" at the Passover Seder with unnecessary (but beautiful) jazzy trills. Remembered visiting jazz clubs across New York City, probably hearing "Take Five" over and over again. Remembered reminding me to play the clarinet myself when I definitely haven't practiced, not once, even though my parents paid for private lessons.

He looked at me this time. Really at me. How was this possible? Why was this possible?

Did it mean anything?

How I think about 'Take Five' now

I wish it meant something. That maybe he was getting better, that the music would somehow shock his brain into working well again. That he could say "David" without hesitation like he did for nearly 30 years of my life.

What I gather it meant: CJD hadn't totally sucked the life out of him yet. The rapid decline was in full swing, of course, but it moved in slow motion too. In moments like this, both painstaking and poignant, melancholy and magnificent, terrible and true. Dad was dying but he was also still Dad. My dad.

We took a break once the song finished. His eyes returned to that stuck place. I filmed his humming, though, and I'm glad I did, so I can look back on it now. Do tears sting my eyes? Yes. But two years later, I press play on "Take Five" and think of him. Sometimes I hear it out in the world, and imagine him humming along. Or better yet, jamming on that saxophone.

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This article originally appeared on USA TODAY: Grief: A son mourns father who died of CJD 2 years later