hi bridgie,
that sounds like such a difficult situation! i'm not sure i can add anything useful that your therapist wouldn't have already covered (i do not have children myself) but i was just wondering if it might be helpful to go to a child psychologist (if his therapist isn't already a specialist in this area already)?
i am sure your therapist has probably also discussed how you should respond to his outbursts, and i don't really want to give any advice myself (i don't know the full story & i am no expert). but i know that being consistent is meant to be important (e.g., if your therapist has advised you to ignore his tantrums, then it is important you try to do this 100%, because otherwise he will know it sometimes works).
im sorry i dont have anything useful to say, i just wanted to say how sorry i am that you're going through such a difficult situation. like lotus said, if this current therapist isn't helping then i would be searching around for a new one

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