Bequeathing for all his sons to perform Hajj and offer sacrifice on his behalf without leaving anything

Q: My father died leaving a number of sons and no estate at all. He bequeathed that all his sons without exception perform Hajj and offer Ud-hiyah (sacrificial animal offered by non-pilgrims) on his behalf. Is it obligatory to execute such a will or it is just an aspect of dutifulness to him and thus each may do them when possible? My mother died and I cannot recall her will. However, before falling ill, she would always ask her children to do the following: perform Hajj on her behalf and offer Ud-hiyah on her behalf. Actually, she left behind no estate. Please, inform us whether it is obligatory to enforce such things or they are merely aspects of showing dutifulness to the mother to be observed, each according to his ability?

A: It is recommendable that you perform Hajj on behalf of your mother when possible and to perform `Umrah (lesser pilgrimage) on behalf of both parents. However, both acts are not obligatory. Rather, (Part No. 16; Page No. 359) they are aspects of good works through which you show dutifulness and gratitude to your parents. Likewise, offering Ud-hiyah on their behalf is not obligatory for you; rather, it is an aspect of charity and dutifulness you show toward them. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.