Our therapist taught us how to use play therapy at home. We had a small room set aside with a variety of toys, it had to include a variety of toy weapons (which we were fundamentally against, but the home play therapy did really help). The child is told the rules, no really hurting anyone, no hitting the head, if the therapist (mom) says to stop we stop, and when the time is up we stop, no extra time. The total session last 1/2 hr, and there are 5 and 1 minute warnings before ending. Then the child can pick any toy to play with and can make up the rules. The adult must comply with the child's rules (other then breaking the hurting rule). Frequently kids who struggle with anger will pick up the weapons and "kill" the therapist over and over.
The therapist reflects what they believe the child is feeling. Reflecting is skill that took several sessions with the real therapist to learn. But basically you state what you believe the child is thinking, feeling or needs to express but can't. It starts out by just saying what the child did. "You picked up the yellow ball", and eventually deeper into the child's feeling. "Wow. you really cut off my arm quickly with that sword, you want to get rid of my sward quickly. Your afraid that if I have my arm, I might hurt you." Your first reflections are never correct, but kids find it easier to correct your wrong reflections then to format their own thoughts. When the child says, "no that's not correct .....", you state, "I was wrong it is ....".
In the play therapy many kids that harbor frustrations, will kill the therapist over and over. And as difficult as this sounds it helps them to manage their frustrations and anger. Frequently after the play therapy they are calmer, and much easier to get along with. I read articles that this helps them develop a feeling that they can have control over what is bothering them.
Thus, if you can not afford the play therapy you might be able to receive some training on ways that you can work with him.