The best they could do is to get a judgement, then send it to a collection agency who will then put it on her credit report. That goes away in 7 years.
I know this from my brother's experience: A towing company that tried to extort $5500 (6 months) of storage fees out of my brother. The car was only worth perhaps $1000..it didn't even run. He told them he didn't want it back AND the law provides for them to dispose of it after 30 days (not 6 months--no reason at all for them to keep it that long!).
They sent it to a collection agency who put it on his credit report. That was about 4 years ago. How much of a problem has this been? Not much--I bought another townhouse and I'm renting it out to him. Plus when he moves out I'll likely be able to sell the townhouse for a bit more than I paid for it OR I can sell MY townhouse and move into that one and own it outright.
In 3 years it's history and the towing company still won't have any of their $5500 (and they'll still likely be calling credit card numbers over the VHF radios in the tow trucks for anyone with a scanner to pick up, but that's another story for another time...)
In your brother's case I would have sued the towing co. for extortion. That's $916 a month. They could probably charge the expenses of disposing the car, but it would be a couple hundred bucks max.
You're right. My husband is a physician, and when he sees a patient that he knows has no means to pay, he just writes it off. Doesn't even bother to attempt to collect past 90 days. If they don't have the money, then suing, contacting credit agencies, etc. is just a waste of time and money/resources