My daughter is separating from her husband because he became…

My daughter is separating from her husband because he became violent while drunk, and police were involved with the result that each time he drinks she must leave the home to protect herself and baby. After months of moving in and out, and his 9 weeks of rehab were unsuccessful and he is drinking again she has come to the conclusion she must separate in order to provide stable home for baby and to remove herself from liability (he drives drunk). She is less concerned about getting any money out of the house as long as her name comes off mortgage, has removed her name from utilities, etc, already, but really wants sole custody and gaurdianship of baby. He is unable to take care of baby by himself (mental illness), but could have supervised visits, but more importantly Sarah would like that just as for the whole life of baby to date she has made all decisions, and been the one responsible, she would want that she make all decisions concerning the baby here on out. (They may get back together if he is able to work his recovery and be sober for at least 12 months....he was still drunk last night.) What do you think her chances are to get sole custody/gaurdianship (are they one and the same?).