myfreedom, it's a bad situation that you can't afford a lawyer. There may be come community resources available to help. You could call into the police station and discuss it with them; you may get lucky and find someone willing to help. You might be able to find pro-bono services online. Someone else has mentions DCS. I'm not sure how it works in the US, but here you can go to your local Member of Parliament's office. The staff often have list of community resources, as well as some influence with agencies.
As for him denying it, well the children told you about it which makes them witnesses. Can you get through to them about the seriousness of the situation? Make an arrangement that they can text you once their father starts drinking away from home, so you can collect them before he attempts to drive?
Hope you can work through this.