The jail would have a social services officer associated with it. He or she will discuss your boyfriend's situation with your boyfriend himself.
You can make some telehone enquiries on his behalf, of course. But I'm sure they will assist him to move to a half-way house as close to you as possible. Your fellow would then get help in finding a job and it will be up to him to make his money count to save for getting a place where you and the baby can join him. I wish you all the very best but this is not going to be easy, you must realise. It is never easy for anybody, just don't get upset about it taking longer than what you think it should. He will need to know that you are on his side, so no getting upset with him, either. Cheers.