My 9 year old grabbed a knife (according to my 7 yo) and pointed it at him. Then DH said 9yo held a poker towards my 4 yo. I told him off and asked him about it and he said he wanted to 'stop them' What on earth can I do to get it through to him how dangerous these are and they aren't to be played with/used as weapons?? I'm scared something might happen. Should I speak to someone about him? He's not overly aggressive, although he will hit his siblings if they upset him.