You were telling my friend he should use letters (one thousand) rather than numerals (1,000)
I disagree with that advice. To me, that is an entirely subjective choice, depending on the type and location of the writing.
You said to leave out "After approximately 20 minutes" in favor of "certain amount of time has passed"
I would agree, but I might have said "after about 20 min" instead of approximately

I'm a very literal person in reading and reacting. I meant no disrespect. The storyline is good and enjoyable