He sounds very frustrated.
I agree that you should try to find out why he is behaving in the way he does and be pro-active not reactive.
I think for a 4yr old it can be still very hard to recognize emotions. First of all I think it’s very important to spend enough 1-1 time with him and chat about everything what’s happening in his life. Some children need more time to adjust and it’s important to prepare them well before a change is happening. Help him expressing it and labeling it.
When becoming physical is his outlet I would create a moment / safe place where he can be physical. Karate for example could be very good to do this in a controlled way.
Published 10th April 2020