Yall need a better lawyer.

If your fathers history is truly clear outside of some parking tickets, in most courts in the country, it'll come down to his word vs. hers. Your lawyer needs to introduce the fact that he does not have a record but your ex step mother does. That will give creedance to the whole story that the argument erupted because he would not allow her to drive because she was intoxicated. Courts are sympathetic women in domestic violence cases, but it seems like your father has a lot more supporting documentation on his side.

Seriously, tell him to get another lawyer if this one is already thinking he's going to be convicted. Good luck.