Well, Gordon's reaction could be complex. On one hand, he might feel honored that Batman has chosen to disclose his identity to him. On the other hand, he could also be worried about the implications. Knowing Batman's identity means he has a greater responsibility to protect that secret. He might start to think about how this new knowledge will affect their working relationship and the safety of Gotham. For example, if the wrong people find out that he knows Batman's identity, it could put him and his family in danger.
The theme of sacrifice also comes up. Both characters are willing to sacrifice a lot for the safety of Gotham. In some fanfictions, they have to make tough choices that show their commitment to the greater good. For example, Gordon might risk his career to protect Batman's identity at times.
The initial Batman story with Barbara Gordon being paralyzed was presented in 'The Killing Joke' released back in 1988. This story had a significant impact on the Batman comic universe.
Well, it might happen when Gordon stumbles upon some crucial evidence or has a moment of realization based on his long-term observations of Batman's actions and behavior.
One popular Batman Jim Gordon fanfiction is 'Gotham's Guardians'. It delves deep into their partnership, showing how they rely on each other in the fight against crime in Gotham. The story has great character development for both of them.
One consequence could be that his enemies might target Gordon to get to him. Since Gordon now knows his identity, if the bad guys find out, they could use Gordon as a way to harm Batman.
Well, it could lead to all sorts of dramatic and unexpected turns. Maybe Commissioner Gordon has a hard time coming to terms with it or uses the knowledge to protect Batman in a new way.