The way I interpreted the prompt was like this:

Imagine if, after your whole life, learning how to use hands and feet, living with the idea that after this it was over, you gave up everything to be with your loved ones. They were with you the whole way. Thousands of great memories. Life changing moments spent with the ones you love.

Then, in a moment, that's all stripped away from you.

You wake up in an unfamiliar body that doesn't feel right, being talked to in a language you understand but don't like hearing, and every single feeling you ever felt deep in your heart was chalked down to nothing but a simulation where none of what you felt was real, and where what you were ripped from turned out to be nothing but pixels on a screen.

How would you react to that?

Of course, I wanted to make it a little more eldritch, so I added some mild body horror and a possibility that the world he woke up in is all a simulation too, but that's the general premise of it. If you want to add another layer to it, I'd love to read it.