help😢

My fiancé got a warrant of arrest for punching my dad in the face. This was half a year ago but he only received the warrant now. He and I are living together and expecting our first baby but my parents don't know that we're still together. The warrant says cops can pick him up whenever and wherever he is if he doesn't surrender. What should we do?? I don't want my baby to be born without a father if my fiancé gets put in prison!😢 My fiancé is a really good guy, he just have a hard time dealing with stress ever since his little brother got killed. Please give me advice on what to do😢
UPDATE:
My fiancé got a lawyer and we had been going to court for half a year now. Him and my dad are good now, and my whole family have been helping him fight this case so that he doesn't go to jail, but California law does  not want me, my fiancé, and our son(due in August) to be a happy family. California is sentencing my fiancé half a year in jail and then 3 years probation. My fiancé is going to lose his job and he won't have anywhere to stay at because we won't be able to afford our apartment! He's by himself here in California! He has nowhere else to go! Why is the world like this!!!??😢