Is it valid for a person who has not reached the age of discernment to perform Hajj on behalf of another?

Question:
And this person says: Your Eminence the Shaykh, does a small child who has not reached the age of discernment have the right to perform 'Umrah, or is he deceased?

Answer:
No, why? He performed Hajj for himself and did not perform 'Umrah, and no one should be deceived. The small child performed Hajj for himself and did not perform 'Umrah. His Hajj for himself and his 'Umrah for himself are not valid until he reaches maturity. However, if a person performed Hajj while an adult, or performed 'Umrah after reaching maturity, and has fulfilled the Hajj of Islam and the 'Umrah of Islam, he may act as a substitute for others who are deceased. He may perform Hajj on behalf of others who are deceased, or for those who are unable, such as a severely disabled person, or a disabled woman. If she is unable to perform Hajj, there is no harm in someone performing it on her behalf.