Hi Starbright and welcome. This is a really tough spot to be in. We have all been there. It is heartbreaking to love an addict. Excuse me if my post seems very blunt but I wish I had this forum 4 years ago when I started a relationship with an alcoholic. I wish I got this advice.
Run away and don't look back!!! This relationship is so new. He has a DUI with a child in the car and he is an addict. If I were you I would end the relationship immediately and go to Al anon to start working the program. Do some soul searching about why you want to be with this person. You may identify as a codependent. Maybe do some reading on this. Stick around here and read the forum.
He will not change unless he wants to. There is nothing you can do to get him to stop.
Put yourself and your child(ren) first. You deserve better.