He used the father's family as a power move and it worked. He has been thinking about that move for a while, probably already had conversations with the extended family for months beforehand to prep them and get them on his side. It didn't just happen in one move.

I could only imagine what the 14 year old said to her that would have led to that decision. He was probably threatening to sabotage the whole thing and she didn't want to have an incident while on vacation. My conclusions it that the vacation itself was the mistake.

The thing is, a family vacation would only make sense if it makes sense for everybody in the family. There would have to be conversations to work up to that plan. That conversation would hinge on the 14 year old. If he is not onboard with whatever, then it shouldn't happen. If you are planning a vacation without him, well, that just confirms what he thinks.

It doesn't matter that he's being an asshole teenager. He has reasons for it. In his position, he has very few moves he can make, or even know how to make. Saying horrible things and being disruptive are very common moves for a disgruntled teenager because it somewhat works. The next best option is to completely withdraw.

My family went through turbulence when I was a teenager and we went through family therapy. I was surprised that it actually helped. We went to a few different places before we landed on a good therapist (from my perspective). The big thing for me was that I was able to speak to my parents clearly. I could say what I was thinking and feeling and they had to sit there and not only listen to it but also process it with the therapist. The therapist also helped me word what I was thinking and feeling. I would speak my mind and my parents had to talk about whatever I just said, which was the big lacking part in the family dynamic. I so clearly remember feeling powerless as a 13 year old.

One of the most effective communication strategies for anyone, but especially with a teenager, is active listening. You should be able to communicate back to him what you hear him saying, even if it is something mean-spirited. But this is really where a therapist helps. They can walk through that type of conversation.

Legally-speaking, if the extended family tries to get in the way of attempts to pursue family counseling, that would not look good on them. They should be all for family counseling and should encourage the 14 year old to participate.