Has he been evaluated for ODD??? It sounds similar to some of the behaviors of my son at that age and he had a combo of things, with ODD being the inflating behavior of everything else. May be worth checking into…it could also be the start of bipolar disease, which drs won’t diagnose in kids that young, but you may be able to get a handle on his highs and lows and dangerous behaviors. Cognitive therapy and maybe a change in his diet (avoiding processed foods) may help. You should have him checked for food allergies also. Sometimes food allergies can cause that, also.