Deputizing others to perform throwing the pebbles for fear of crowdedness

Q: When my mother performed Hajj, she completed all the obligations, except for throwing the pebbles at the three Jamarat (stone pillars marking the pebble-throwing areas, Jamarat-ul-`Aqabah being the closest to Makkah). She threw pebbles at only one of them, and authorized someone to throw the rest on her behalf with no Shar`y (Islamically lawful) excuse. In fact, she was afraid of the crowd. Please take into consideration that this was the only Hajj she performed. Is her Hajj valid; if not, what should she do? (Part No. 10; Page No. 318

A: If your mother authorized someone to throw stones at Jamarat on her behalf, for fear of the crowd in the pebble-throwing enclosure, her authorization is valid and there is no harm in this.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.