She told them "I'm on Social Security for $1000/mo, I'll pay you $50/mo". It was basically that or sending it to collections and never getting a dime from a retiree. So they accepted and told her a "non-profit" paid for the doctor's portion of the bill, which was all but about $40k.
She'll probably be around another 10 years max, which means she'll end up paying about $10k of that balance.
Medical debt is the least concerning type of debt for most lenders. If you ever fall into this hole, don't sweat it. [Unsolicited advice.] Just let it go to collections. You'll get harassed for a little over a year. Debt older than a year is almost never pursued by collections agencies. After things quiet down start sending letters to the credits agencies saying the collections debt has been settled. The collections agency will usually slip up and not respond at some point and it'll be gone from your credit history.