The moral might be that greediness leads to downfall. The greedy doctor in the story, probably because of his excessive desire for money or gain, may end up in a bad situation, like losing his reputation or facing some form of punishment. It shows that when people are too greedy, they forget about basic ethics and values, which can have negative consequences in the long run.
One possible moral of the 'old lady and greedy doctor story' is that kindness prevails over greed. The old lady may be in a difficult situation and relying on the doctor's kindness. But if the doctor is greedy, he fails to show that kindness. In the end, the story might be trying to show that those who are greedy will not succeed in the long term, while those who are kind, like how the old lady may have been kind in her own way, are the ones who will ultimately be rewarded, even if not in a material sense.
Well, the moral could be that honesty is the best policy. The old lady might represent innocence or someone in need of genuine help. If the doctor is greedy, he's not being honest in his intentions towards the old lady. Maybe he overcharges her or gives her unnecessary treatments just for his own benefit. This story could be teaching us that we should be honest in our dealings with others, especially those who are vulnerable like the old lady.