A mother wants her sons to waive their shares in their father's property for their youngest sister in order to reconcile between them and for their mother to be satisfied. They are confused, whether to give preference to their mother's satisfaction or receive their lawful right in their shares of the inheritance?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

The sons are not required to obey their mother in this regard. Nevertheless, they are required to be dutiful to her, speak kindly to her, try to convince her in a good manner and seek the intervention of those who can convince her.

If they want to waive their right in their inheritance voluntarily for their sister with the intention of obeying their mother and seeking her satisfaction, this will be better undoubtedly. 

Allaah Knows best.