This is wild. This is not from Kafka: this poem was burned into my brain when I read it.
It seems the quote being attributed to Kafka comes from a submission on Goodreads, then picked up by bots. The lettter is not written with his father in third person. The writing style of the poem is also much more modern.
The letter (latest translation I believe) can be found here (I joined Scribd specifically to download and host it myself, because I couldn't find it free anywhere!). This is a blog on it that I thought was interesting while looking for the letter itself.
Some excepts:
"You asked me recently why I maintain that I am afraid of you. As usual, I was unable to think of any answer to your question, partly for the very reason that I am afraid of you, and partly because an explanation of the grounds for this fear would mean going into far more details than I could even approximately keep in mind while talking.
. . .
I was a timid child. For all that, I am sure I was also obstinate, as children are. I am sure that Mother spoiled me too, but I cannot believe I was particularly difficult to manage; I cannot believe that a kindly word, a quiet taking by the hand, a friendly look, could not have got me to do anything that was wanted of me. Now you are, after all, basically a charitable and kindhearted person (what follows will not be in contradiction to this, I am speaking only of the impression you made on the child), but not every child has the endurance and fearlessness to go on searching until it comes to the kindliness that lies beneath the surface. You can treat a child only in the way you yourself are constituted, with vigor, noise, and hot temper, and in this case such behavior seemed to you to be also most appropriate because you wanted to bring me up to be a strong, brave boy."
The poem the quote is from is a woman on, I think, TikTok? I am sad I don't have the attribution on the picture I took. But I still have the poem saved:
The poem:
My father is a good man. Sort of.
He is good when I compare him to
His own father, and that's enough. I hope.
My father and I are more alike than
I'd care to admit, and whenever I feel
Pure rage, I know I am my father's daughter.
My father has gotten... better.
I cannot help but wonder if it is too late.
He now asks me why I am so
Angry, why I raise my voice.
He does not understand that
I learned it all from him.
I know it is my father's first time
on this Earth, too. And I know
He had it worse when he was little.
But I was little too.