New York State Adoption?

My boyfriend has physical custody of 2 children that are not biologically his, the mother took off, hardly in picture, the real father is totally not in the picture and we have no way of finding him. He wants to seek divorce, but his workplace told him that he would have to adopt the 2 children to keep them on his insurance, if he is to get a divorce. Any one been through this at all, and what is the best way to go on it, I know to contact a lawyer, but want to know what to expect.