You have good grammar and English usage in the paragraph. "Mr" should have a period following it though: "Mr. Koh"
Also, this sentence is correct, but possibly confusing as to whether "he" and "him" refer to the dog or Mr. Koh:
"He followed the dog to where he led him."
You can rewrite it to be clearer, or let the reader figure it out by context. That is your choice though. Good luck!
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