A man pointing to a lady said, “The son of her only brother is the brother of…

Concept:

In a “pointing to …, he said” relation problem, each relationship phrase is resolved against its OWN stated anchor — “her only brother” is anchored to the lady being pointed at, while “my wife” is anchored to the speaker — so the chain is built by tracking whose relative each phrase names, starting from the innermost phrase and working outward. The identity that carries such a chain is the sibling rule: two people who are brother and sister to each other share the same parents, so naming somebody’s brother also fixes who that person’s father is.

Application to this statement:

1. Call the lady L. The phrase “her only brother” names exactly one man; call him B, so B is L’s brother. The word “only” matters: it guarantees B is unique, so the next link cannot be ambiguous.

2. “The son of her only brother” is therefore B’s son; call him S.

3. The statement equates S with “the brother of my wife”. Call the speaker’s wife W. S is W’s brother, so by the sibling rule S and W have the same parents.

4. S’s father is B (step 2), so W’s father is B as well.

5. W is the speaker’s wife, so W’s father B is the speaker’s father-in-law.

6. L is B’s sister (step 1). Hence L is the sister of the speaker’s father-in-law — in everyday terms, his wife’s paternal aunt.

Cross-check against the other kinship terms:

• “Mother’s sister” would put the lady on the sibling line of the speaker’s own mother, but no link in the chain touches the speaker’s birth family — every step runs through his wife.

• “Grandmother” would put her two generations above the speaker on a direct ancestral line; the chain places her only one generation above the wife, and laterally at that.

• “Mother-in-law” would make her the wife’s mother, i.e. B’s spouse; the chain makes her B’s sister, which is a different position in the same generation.

• “Sister of Father-in-law” is exactly what the chain produces: sister of B = sister of the wife’s father = sister of the speaker’s father-in-law.

Reading the chain backwards confirms it: if the lady is the sister of the man’s father-in-law, then her only brother is the wife’s father, that brother’s son is the wife’s brother — which is precisely what the man said.