Is it obligatory on an old blind woman who can afford Hajj to perform it herself or is it permissible to delegate someone to perform it on her behalf?

Q: There is an old woman who has hit her seventy years of age and is blind. She is well off, can afford the cost of Hajj, and desires to perform it. She has three sons. Now, should they accompany her to perform Hajj despite her old age and blindness, or it is permissible for her to delegate someone to perform Hajj on her behalf in this case? Give us a Fatwa, May Allah reward you with the best. May Allah benefit people with your knowledge. (Part No. 10; Page No. 53

A : If the old woman mentioned above is able to reach Makkah while riding and has a Mahram (spouse or permanently unmarriageable relative) who can assist her, then it is compulsory to go and perform Hajj. If she cannot reach there but she can afford the cost, it is obligatory on her to delegate one of her sons or someone else to perform Hajj and `Umrah (the lesser pilgrimage) on her behalf. If she is poor and one of her sons took upon himself to help her with the cost of Hajj, either to perform it himself or delegate someone else to perform it on her behalf, then it is permissible to do so.May Allah grant us success. May peace and blessings of Allah be upon our Prophet Muhammad, his family and his Companions.