I think it was the wife who the OP quoted as saying the Guy deserved his weekends as he works hard and pays for their school fees (presumably the parents chose to send them to private school, so why make the kids feel they beholden for it?)
Haven't read all of this, but my DH is also sailing mad, and we used to have a caravan and boat.
Suffice to say, the caravan is now sold as we worked out it had only been used twice in the last year we had it, and the boat is at a sailing club where it gets occasional visits during the summer months
.
The kids will ultimately vote with their feet, as DS1 started to at about aged 12 (well, he vocalised his lack of interest which soon translated into me willingly staying at home with him).
I think there are, as someone said, two camps of parent, though; it's a question of whether these boys will be able to make their dissenting voices heard.
I'm with them on this; sailing gives me no pleasure whatsoever - in fact, I find it distressing and scary - a weekend forced to do it would be torture. It's not the same as being dragged around stately home or shopping malls - it can be genuinely frightening and uncomfortable in the extreme.