Your lawyer will want to see if his behavior (addictions, dangerous high/low moods) will affect the children. If he cannot get it under control or won't go for treatment, then you most likely will be shown to be the more stable parent.
The judge could award physical custody to you...but he gets access time but the majority of the time, the children could be with you....it will depend how knowledgeable your lawyer is in court.
Stay out of his treatment...let him solve his own problems now.