Homeless addict with underfed dog

I have a bit of a conflict here: There is a young woman frequenting the u8 with her german sheperd asking for money. She is obviously using and living on the streets and today I bought her packs of special dog food due to the kidney deficiency the dog has. The thing is, that the dog is extremely skinny, and while he seems already pretty old, thats not how a healthy dog that age should look. I know that there are people on the streets putting their animal partner always first, but here it seems that the woman is not able to put her addiction second (or maybe she does but its not enough). Although I would shed away of actively seperating her from probably the only friend she got left, the health and wellbeing of her dog worries me. Has somebody expierenced something similar? What did you do?