Its not easy to get a teen to go to a councilor willingly because the teen probably feels that they are a normal and going to a councilor would be bad for his social standing if anyone would find out.
I’m not exactly sure why you want him to go to a councilor, but if you want him to go to repair your relationship with him then try telling you that he is doing you a favor by going with you. If you want him to talk to a councilor about remaining religious, then I’d suggest having a rabbi/rav who is close to him go over to him and talk to him.