as I was looking at the wallpapers of Freddie and Freddie and Jack,especially the one from the piano bar one with the words to the theme song on it.
You can see the love they have for each other, and in her book Maria says it was hard for Karl to be closer to Freddie because he was an older Father and because he worked hours that he was away when Freddie was awake.
I was wondering if Karl may have envied the relationship Jack had with his son.
what do you think about that?

Maybe he was , But read that Mr. Prutzel wasn't very expressive with Freddie. May he didn't let it show if he was.