What does "とこの" mean here?

Question

Sentence is:

うん俺の嫌いな杉木さんとこの一人息子な

Translation is:

Yup. The only son of the Sugiki I hate.

What does とこの do here?

Answer 1

杉木さんとこの is semantically the same as 杉木さんのところの ("of Sugiki's family").

• とこ is colloquialism for ところ ("place", or in this case "house" or "family").
• The particle の before ところ often turns into ん in speech (e.g., 彼のとこ → 彼んとこ, あいつのとこ → あいつんとこ), but when there is already ん before it, the double ん will be contracted to single ん. For example 奥さんのとこ(ろ) contracts to 奥さんとこ, not 奥さんんとこ .