Me and my husband need to take in a child please help me with some details?

We aren't rich but we are middle cl. We afford what we need and are modest about our spending so we do ok. We want to take in a 16 yr old that has nowhere to go. He gets child support sent to his mother, well modest amount but nontheless something. My husband wants it to go to the son for clothes and things he needs not to the mothers drug habit. We think emancipation might be whats best? And we already pay close to 500 a month in insurance for our family so it would be really costly to add him, he gets medicaid now if he moves in can he still receive it or will they base it on our income? My husband doesn't mind him coming to live with us and us helping him through school and get to college but he cant take on anymore financial responsbility as far as a child thats why he has had a vasectomy. Ok so what do we do? I am going to talk to social services later but i am just wondering if anyone else had any insight or advice? I think I can make such a difference in this childs life and I cant stop thinking about it. I dont want to just turn my back on a helpless child who just needs a chance.