I think you are very resourceful and smart there kiddo. I'm glad you've come here to seek advice. And I'm really sorry for the situation you are in. When you go to counseling, does your mom come with you? Do you think it's something the three of you could talk about together in a session? I've just spent months in counseling with my son over my past alcohol use, counselors will do their best not to break families apart, they will only call if you are in real danger. You could always feel your therapist out first, before telling him, by asking him what his rules are for when he makes the judgement call about calling DHS.
What about your grandparents? Are they around to help you?