Simon Cowell weinte ununterbrochen. Der Junge sang ein Lied, das Simon sprachlos machte. Er ging auf die Bühne, um den Jungen zu küssen.

Yes, it does sound like a very touching moment!

Unfortunately, without more context or specific information,

I can’t recall or identify the exact song that the boy sang that moved Simon Cowell to tears.

If you have any additional details or if the song’s title is provided, I could try to assist further.