Both my mother and a great aunt's friend has had a problem like this.   Albeit much worse than the woman's!  

My brother was constantly high on drugs of various sorts and even stealing from my mother, and inviting all sorts of drug addicted women over to 'spend the night' at her apartment and later house.  

She constantly complained about this, but ultimately did nothing!  It only ended when me and my husband went over there and packed up his things in front of her, and stayed there so she'd tell him to get out (the used crack cocaine spoons and spent injection needles we found only shocked her, sadly - not us)!  

The lesson is that if you can't do it yourself, get moral support and friends and family to help you do so.