You're assuming they have no other debt, as medical debt doesn't influence your credit and you can't be forced to pay it unlike other forms of debt, making it the last form of debt to pay off (and most have some larger crippling debt that comes first). You're assuming they're paid more than minimum wage (~15k a year), so 1/15 of their yearly income, and that already cannot afford housing and food. You're assuming they have a consistent income and aren't seasonal only.