James has a sister named Sophie. Sophie is married to Alex. Alex's sister, Maria, has a son named Daniel. What is the relationship between James and Daniel, and how are Sophie and Maria related?

Respond very briefly.
James is the uncle of Daniel. James's sister is Sophie, and since Sophie is married to Alex, Alex is James's brother-in-law. Alex's sister is Maria, making her the sister-in-law of Sophie. Maria's son, Daniel, would then be the nephew of Alex and by extension, the nephew of Sophie since she is married to Alex. Therefore, since Daniel is Sophie's nephew and Sophie is James's sister, Daniel is also James's nephew.

Sophie and Maria are related by marriage; Sophie is Maria's sister-in-law. Maria is Alex's sister, and since Sophie is married to Alex, that creates the sister-in-law relationship between Sophie and Maria.