I have read 8 pages on the subject now and want just to make a simple comment.
The original boater may have made a wrong decision in carrying on after a breakdown (debatable, after all, he thought he had fixed it).
He had his small children aboard (nothing wrong with that, he said they had jackets on, his choice to choose that life-style, many of us would love to do the same, given the choice)
He had the correct equipment, even if he had failed to use it
He felt he and his family were in danger and needed help, which he requested of a passing boater.
If I had been that passing boater and had felt I needed to get to somewhere in a hurry or that I was incapable of stopping to help, at the very leat I would have stopped to check no life was in danger and perhaps to suggest deploying the anchor. At all times we should slow to pass boats at rest, well moored or precariously held by spindly trees. If the other boater had done this he would at the very least have been able to offer advice and seen the plight of the stricken boater.
I am a nurse and see it as my duty to render such aid as I am capable of doing whenever it is needed, not just when it does not put me out unduly. I hope (although I do not expect) that others might do the same for me.
Those of us who use the waterways are a small community. Let us just remember we need to be community spirited and work for the well-being of all (except perhaps the scum-bags who pinch and damage our boats and their equipment!)