He is being charged with third degree assault - domestic violence. That is a charge that carries $500 to $5,000 fine and from 6 months to 24 months of jail. It is a very serious charge - the highest level of misdemeanor and he DEFINITELY needs legal counsel to represent him. He can either apply for a Public Defender or look around for a private attorney. I have found that the attorneys on Avvo are excellent with years of experience and great people skills. Plus, most of us offer a free initial consultation. So, shop around and good luck.
I agree with the prior answer... better get a lawyer... It can have significant criminal consequences, as well as child custody consequences and even immigration consequences. It isn't something that you plea guilty to under any amount of pressure without first seeking a competent attorney for advice.