So she grew up in a poor, but very large, family - So I totally get them not affording proper care, but why would she die alone? Wouldn't her family be visiting her? Wouldn't they be there beside her on her death bed?
If they wanted to emphasise how alone she was, why put her in a big family? Say she's a single child in a family of workaholics, who hadn't noticed her failing health until it was far too late, or something similar.