We are Italian citizens living in Germany. We would like to go in vacation to Italy with a Nigerian friend and her child. While the child has German nationality and passport, she is a legal resident in Germany but with Nigerian citizenship.
The problem is that we would like to go in August and her passport expires in September. Does the six month validity rule for the passport apply also to travels inside Schengen area? We could not be in time to renew the passport so we worry about what could happen to the woman.
Note: I searched a lot for info also here, but all the answers I've found were for people who intended to enter and then leave Schengen, there is no case similar to ours where a "third party national" already lives in Schengen and wants to travel inside.