How can parents be persuaded to approve the marriage of their paternal aunt's daughter to her maternal aunt's son who suffers from anemia?

If the aforementioned young man is a person of religion and good character, then the Shariah encourages marriage to him, based on the Prophet's (peace be upon him) saying: "If someone whose religion and character you are pleased with proposes to you, then marry him. If you do not do so, there will be tribulation on earth and widespread corruption."

The mentioned anemia condition does not fall outside of two scenarios:

1. If it is mild: In this case, try to convince your parents to agree to the marriage, seek help from others, and make supplications. If they cannot be persuaded, there is no sin in marrying without their consent, especially when there is fear of tribulation. 2. If it is severe: If the illness affects marital life, then it is obligatory to obey the parents in their refusal, because obeying them in what is good is a duty.