the case seems to be a bit complicated. As there is a lawyer involved I would address him with the questions you have. It makes no sense that we on this online-platform "guess" what the Ausländerbehörde plans or if they made a mistake. The lawyer or your friend must contact the Ausländerbehörde to answer your question.
By the way: Did the letter from the 24th actually say that he will get residence permit?
I am sorry I have no better answer for you.
I hope my answers were helpful and I would be very happy if you would contact me again with further questions. I'm a consultant with mbeon and I‘ll be glad to help you over a longer period of time. Mbeon is an online advice for migrants via the mbeon app, which you can install on your smartphone for free. Download it from App Store or Google Play Store. You can find me in the mbeon app and get confidential individual advice in a secure virtual space without other people reading our conversation. Further information: www.mbeon.de.