I used to visit an elderly woman who lived alone and had never married. On one occasion when I called, she fell and hit her head on her bathroom sink...fortunatley I was able to get her to hospital. To cut a long story short, she did have a niece who lived some distance away but had been visiting as often as she could. I telephoned her and she basically took control of the situation. The lady was assessed and eventually did move into more appropriate accomodation with the support of her niece. So perhaps uyour neighbour has a sister or brother or other family members that you could contact? Otherwise, could you have a descreet word with her GP?