I say, and with God's success: His ablution is not invalidated; rather, only the prostration is invalidated; because it is a condition for laughter that invalidates ablution to occur during a prayer that involves bowing and prostration; and this condition is not met in the prostration of recitation; and because the text here is contrary to analogy, it is limited to its specific case, which is the absolute prayer, so it is restricted to it, and thus there is no event outside of it. Al-Daraqutni reported in his Sunan from Anas (may Allah be pleased with him): "The Messenger of Allah (peace be upon him) was praying with us, when a blind man came and stepped into a filth on the ground, and he fell down, and some of the people laughed, so the Messenger of Allah (peace be upon him) commanded those who laughed to repeat their ablution and prayer." See: Sharh al-Wiqayah, 2: 33-34, and Tabyeen al-Haqaiq, 1/ 11, and Fath Bab al-Inayah, 1/ 68, and al-Ikhtiyar, 1/16-17, and Mukhtalif al-Riwayah, p.344-345, and Allah knows best.