in this for the long haul,
I agree with you, and it is extremely well said that they have been PUT in this situation. I know that when it counts I will still stick up for them, and will relate to H what is necessary. I just did exactly that with my SIL, actually, explaining their feelings about an issue related to all this.
What I was trying to do with telling my kids that was to encourage them to trust themselves, and to start the process of teaching them about this. Mine, like what you say about yours, are scared -- very scared -- that anything they say will make things worse.
I have the same thing -- they are polite to H, even polite to OW when they end up seeing her, and scream and cry to me. One reason why I wanted them to talk for themselves is that for the past few years I HAVE been telling H what they say, think and feel, and that is now coming across as me just nagging.
So at least one S has been expressing himself, not that H is listening. So kids and I end up having conversations on selfish behaviour, free will, choices that have been made, and so on. I've also said that I think he does love them, and in the end will respect them more for being honest. That he may get angry or seem to move away further for a while, but in the end the reality may become more evident for him.
It's a tightrope, isn't it?
Please, more comments on this general topic!