I don't have any answers, but DS7 also has this phenomenon of getting very, very upset about something that really isn't worth it. These days he doesn't usually show it in bad behaviour but I think in a way that makes it worse! He says, "I don't want to exist any more". I remember only too well what it's like to be a child and in this state; these words are not exaggeration, they are really how he feels at the time. (Sometimes! He *also* uses the same words for effect sometimes, although the difference was pretty obvious and I hope I've succeeded in letting him understand why that's a really bad idea.)
All I've found so far that seems not obviously wrong is:
- acknowledge the feeling, but reword to something a bit more directly descriptive, getting rid of the proposed solution (not existing), e.g. "You're really really really upset about that, aren't you?"
- but at the same time be calm and practical about whatever the actual problem is
- later, talk about how these really deep feelings are real, but temporary. I pointed out explicitly that most other people don't get these really strong feelings about small things, and that that can make it hard for adults to react to; and I talked about how people were always telling me not to overreact when I was a child. This did seem to help (especially since I'd just made the mistake of doing a bit of that, so it made sense of it to talk about how helpless you can feel when someone else is so upset and you don't understand why or what you can do about it).
TBH I still have this tendency as an adult; the things that help me are knowing that it passes, knowing that when calm I'm good at problem solving, and having people around who love me unconditionally.
