If it were me, I would be talking to the people who are sending the lollies for the kids. ExDH is a twat, we know that and he's proven he will stoop to very low levels to hurt you so if it wasn't this, it would be something else and you expect that sort of thing from him, but like you said DS isn't hurt about that so much as what the friends have done and I think it is important that they are told just how much this has hurt DS because it is beyond reproach that friends are getting in on the mind and power games as well, take sides fine, but don't participate kwim? and it's disgraceful that they think it is OK to deliberately exclude one child simply because he chooses not to visit his father. I'm sure that you can think of a nicely worded email, or better still a phone call because it is harder to back away from someone you are speaking to but you can ignore an email.

I think what Kaz has suggested are great ideas, but the kids shouldn't have to do all that kwim? They shouldn't have to learn strategies to cope with adult manipulation to avoid getting hurt. So if what they have done is spelt out for them, maybe they will realise that what they are doing is pretty rank and will stop it completely, or at least send an extra bag for DS.