thank you for contacting the wefugees community.
I suggest that your fiancé goes to the local registry office and asks, what documents are needed. Your case is really special. I am quite sure that not every registry office in Germany would handle your case the same way. So it would be best to explain to them what documents you have (including the foto) and what else you should bring. And you must mention the asylum procedure, which means your fiancé cannot simply go to his embassy and apply for papers. The staff at the registry office is probably not familiar with asylum law. To be sure there is no misunderstanding, your fiancé should take a translator to the appointment.
I hope I could answer your question! Please note that this is only general information that cannot replace qualified legal advice.