Brookyln, a talented footballer in his teen years, had a spell with McCool inside QPR's academy, while he was also signed by Brentford as a senior player last year.
Reacting to Brooklyn's fued with David Beckham and wife Victoria, McCool posted to LinkedIn: "Brooklyn Beckham getting piled on. But I felt sorry for the lad. I did see some bizarre carry on as his football coach at QPR & certainly seen the anxiety.
"He might have got this situation wrong, I'm not on either side because I don't know them & his parents were always polite to me. But I did witness myself a strange dynamic which is impossible for us to judge and predict how we would navigate it, both as parents and as a young person.
"My short window into that life left me some funny stories, also some sad ones and I realised how tough it must have been for the lad. Yet I coached many lads of famous parents, mostly well-known footballers.
"But this spell was on another serious level. It would make a good chapter in my book. What it did do was open my eyes. Being a super wealthy & famous doesn't always lead to happiness.
"It's hard to 'sympathise' or empathise because most of us will never know. But being flanked by permanent security at 14, plus the many other things I seen made me realise I shouldn't judge because I haven't walked a mile in them shoes, or his parents to be fair.
"I am sure they will close ranks and resolve their differences. I hope so. (& David thanks for paying me back that £6) (laughing emoji)."