@JPB,
Thanks for the explanation about how this forum works.
Regarding the length of the incident, it was a matter of seconds. We (my husband and I) approached the tree when the man was already on top, and our son was just climbing up. He had barely straightened up when the man said, "Don't follow me, get down". There was no urgency in his voice, and I asked, "Why the hell did you even get up there?" (because this is not the thing he would usually do), and he replied, "Stupidity, I guess". Then he said "get down" to our son for the second time (again, there was no urgency in his voice; I could see he was irritated, but didn't look scared), and when our son didn't move, either me or my husband, I don't remember who exactly, told him to get down now, and he did. If you've been wondering, we've spent A LOT of time with this couple, we know them REALLY good (at least I thought we did), so I'm pretty sure I'd noticed if the man was scared or felt uncomfortable on that tree. That's why what followed came as a complete shock to all of us.