Albreicht is not a terrible friend for refusing to allow Nora participate in the duel, his was actually just being a good dad for this first time in the whole series.
He may be a bad dad, but he is a surprisingly loyal friend who has very clear line that he will not cross. He definitely would not have left Shuli for dead in this situation.
I would like to agree on the first but I also don't know since clearly his loyalty never once lies with his family. It was with the royal family. I think he's trying to cut his losses by not letting Nora in on the fight and lose (which he won't, but homeboy doesn't even know his son enough to trust his strength) because if Nora loses then the church will be able to curb both the Neuschswantein and Nuremberg which would then be dangerous for the royal family and the nobility.
But then again he's a fictional dude so who knows
Cardinal Richelieu CLOCKED IT SO BAD He KNEW Nora was gonna kick ass thats why he's begging the Emperor. Also Albrecht Nuremberg u were a shitty father and ur about to be a terrible friend. Let's be fucking real here!!!!!!!