My son, almost 9, is having what I think are sensory meltdowns. It's always triggered by frustration. He cannot tolerate me telling his sister off (she's 13) if he thinks it's unfair and he steps in if I have a disagreement with my husband and voices his opinion as if he was an adult. We have explained to him he must stop doing this as he is a child and we are the adults, but he can't help it. He told me this morning that if someone is being mean to someone else he needs to defend "the victim": last night I was nagging my daughter about cleaning teeth and going to bed, and I asked her to do it "immediately", and according to my son this is unreasonable! He was tired and had a meltdown.
He worries about everything and this gets him anxious: me and his dad dying in the future, where he's going to live as an adult if property prices keep rising (!!!), his sister being home late from school, accidents (plane, car, train), earthquakes (if we travel anywhere he'll ask if the area is earthquake prone), etc.
He is an extremely loving and affectionate child, extremely curious, knowledgeable, inventive and articulate.
He's great company but his anxiety seems to come from asynchronicity: he lacks the maturity to tackle adult worries and disagreements, but he insists on doing so.
He is also dyslexic and this contributes to his frustration -- his achievement at school is average although teachers realize that he is exceptional. He is always more anxious during term time.
Any experience of similar situations would be appreciated!