Hi, I'd like to help you with your question.
It is good that your son is willing to see a counselor. It will help him find the reason for his depression and anger and develop better ways to cope.
However, if you feel your son cannot wait to see the counselor, but he will not go to the hospital, you may need to file a 302. A 302 is a legal document that states your son is either suicidal to the point you feel his life is in danger, homicidal or he is unable to care for his own basic needs.
In order to file a 302, the person filing needs to be the person that hears your son say he wants to hurt himself or someone else, or they need to have seen first hand that he is unable to care for himself. They can go to the ER and file there. The staff will review the 302 with a doctor and if the doctor feels there is enough evidence to enforce the 302, they will send the police to pick your son up. The police go because the 302 is a legal document and just in case your son resists.
The ER will then evaluate your son and admit him if there is sufficient cause.
This is the only way you can force someone to get treatment against their wishes. Otherwise, it is best to try to convince your son to go to the ER for an evaluation. If he will not go, then you can either wait for the counseling appointment so the therapist can evaluate him and support your wish to take your son to the ER, or try to see if he is willing to see his family doctor. Sometimes the doctor can convince someone to get help when family members cannot. The doctor can also prescribe medication which may help your son feel better until he sees the therapist.
I hope this has helped you,