You're not abandoning him, you simply don't have the resources to bail him out of his mistake. Be supportive when he calls, and try to faciliate any arrangements you can to help him. He's freaking out thinking he won't be able to see a judge till Monday, but there are other ways of getting out that he might be able to take advantage of and don't cost any money. Depends on the offense. (I am not asking for information, I don't want to know - it's only a statement)
You can try calling a bail bondman and seeing how much $$$ it is to get him out. The thing is, if you don't have any extra cash laying around JUST WAIT until he sees a judge. Things will get sorted out and you all will know exactly what you need to do (come up with money, or he might be able to walk on his own).