How Can I Get an ICE Detain-er Removed?

My boyfriend came here from West Africa on a refugee program when he was younger. He recently got arrested for violation of probation in late October and was sentenced to six months. When he got arrested he was in Pennsylvania and they placed an ICE detain-er on him. He later got transported to Maryland, at first they did not know that there was a ICE detain-er placed on him but they later found out. When ever they checked in the system his status says investigating, it doesn't say that he will get deported or not. And they haven't served him with any papers saying he will get deported like some of the other inmates have. He is currently a green card holder and he doesn't have any major charges, they are mainly for possession of paraphernalia.His release date is in mid February. My question is, will they pick him within the 48 hours or is it likely that he will get deported or will they hold him for a while and then release him. Or Would they not come for him at all. And is there any paperwork that can be filed to remove it. He is in the process of registering for school and turning his life around, he is only 20 years old.