Pointing to a man, a lady said 'His mother is the only daughter of my mother'. How is the lady related to the man?

Introducing a man, a woman said 'His mother is the only daughter of my father'. How is the man related to the woman?

Pointing to a photograph, A said to his friend B: 'She is the only daughter of the father of my mother.' How is A related to the person in the photograph?

Pointing to a woman, Nilesh said, 'She is the only daughter of my wife's grandfather's only child.' How is the woman related to Nilesh?

Pointing to a photograph of a girl, Rajan said, 'She has no sister or daughter but her mother is the only daughter of my mother.' How is the girl in the photograph related to Rajan's mother?

Introducing a man, a woman said, "His sister's mother has only one son who is the husband of my father's only daughter." How is the woman related to the man?