A women has two sons, A and B. The son A has denied to keep her, take care of hers and give her food. The woman strongly loves Son A but not Son B. So, she decides to stay at Son A for most of the time and come to Son B for food, to sleep, to use toilet and for her medical expenses. Is it wrong if Son B denies her these services?
Confucian ethics would say we owe our parents a debt we can never repay, and that to be respected ourselves we must have a culture of respect for those that preceded us (I argue Confucian thought emerged from a society with extra high costs to succession crisees here: Why is Confucianism considered a brilliant philosophical school of thought?). A Greek proverb says “A society grows great when old men plant trees in whose shade they shall never sit”, and I think there is a human cognitive flaw around struggling to grasp the impacts of coumpound interest, in relation to repeated inheritance rather than just a single instance of inheritance.
There are various ethical frameworks to work from. I'd say you implicitly are suggesting a transactional ethic, that could be related to game-theory: son B is offering food so the mother owes a debt, son A is getting something -love- so owes something back to the mother.
Very few ethical systems support reasoning like that, even if there are realpolitik or evolutionary reasons to see game-theory selfishness as the stable equilibrium, the 'default'. Ethical theories usually try to support an unstable equilibrium of mutual benefit, eg parents offering unconditional love, and children being considerate of others rather than only thinking of themselves, as values that build a better society even when they oppose short-term personal interests. When we say someone is acting morally, and is a good person or to be admired, we generally have in mind they are raking on personal costs or problems for the benefit of others, putting wellbeing of others ahead of their own.
Stoicism is a perspective that seeks how (and why) to act well regardless of the behaviour of others, in order to cultivate inner qualities. In that perspective there is an opportunity for son B to cultivate 'being the better person', and so build inner freedom in choosing what kind of person to be, regardless of the others involved.
I think of intersubjective ethics as underlying a lot of moral reasoning, like Kant's Categorical Imperative, or Rawl's Theory of Justice. Discussed here: Is the Categorical Imperative Simply Bad Math? :) I would relate this not just to being the kind of person you want the world to have in it, but as pointing to the power and benefit of trying to put ourselves into the minds of others, as helping us move towards a stronger and more capable network.
Prima facie we will feel that the denial of services of Son B is right. But actually it depends on many factors.
To clarify this, let me ask these questions:
- Why does the mother not love Son B? Shouldn't there be a reason for this?
- If Son B is richer than Son A, can anyone say that Son B's attitude (denial) is right?
- Can we never say that her behaviour is to make Son B a better person?
- If a son doubts his mother, will that doubt ever make him a good man?
So, IMHO, under normal circumstances, no mother should be denied these services.