will he get off?????

I live in Massachusetts,I am going thru somewhat a messy divorce, trial set for next month. My STBX was arrested a week ago for OUI. He is currently on probation because of a physical abuse guilty finding from last November. Other guilty OUI's but there are just past the 10 year mark. He refused breathtest on arrest. We have two children. He has court ordered visits with his kids one night a week. Also a court ordered no alcohol order 6 hours prior to visits.
(I was told by a friend that he was arrested. It took him 5 days to tell me what happened, and it was only because I finally called him and asked if he had something to tell me.)
Here's my concern. He is an alcoholic but of course he is claiming he was not drunk. He is also being charged with 2 motor vehicle violations but he won't tell me what they are.
He says the police smelled alcohol on his breath and it's the only reason why he was arrested. BUT THEN HE REFUSED THE BREATHTEST! NOT HARD TO FIGURE THAT OUT!
He says he has a witness that can say that he was not drunk.
His araignment is the 1st of next month before our divorce court date and I am thinking he going to get off on that date. Does being on probation mean anything?
What happens at the araignment and can he get the charges dropped on that date? What does his claim to having a witness to testify for him hold against having the police feeling the need to arrest him for an OUI.
I have been concerned for my kids safety thru-out this whole sepration/divorce and that is why I was able to get the court ordered no alcohol order.

HELP!!! Any advice on any part of this will help so much. I am just sick over that fact that he's going to kill someone because of his drinking someday or again, (again meaning because in the last 6 years while we were married he got away with his drunk driving because when he got in an accident he left the scene of the accident then turns himself in the next day when he's sober) get off the charge because a friend is going to lie and say he wasn't drunk.

idna