how can i help my boyfriend/father of my son not get deported?

Hi, so my question is how I can help my boyfriend/father of my son not get deported. He was brought to the U.S. when he was around 4 years old by his mom. He is now 22 years old and recently got in trouble with police. He had a rough childhood with his mom, she physically abused him up until the age of 16/17. I do helieve there is evidence from when he used to live in chicago,IL with his mom. He only went up to freshman year in highschool due to his mom making him drop out. We were supposed to get married pretty soon, he wanted to buy me a decent ring so he wanted us to wait to get married. He just recently got booked to a county jail, the judge gave him 20 day sentence with huber, but he called me yesterday telling me that police wont let him get out to work and that immigration has a hold on him. I need help/advice on how to help him. We have been together for almost five years, and have a two year old son. I don't know what to do, my son doesn't stop asking for him.