I say, and with God's success: His ablution is valid; because the aim is purity, and it has been achieved without the order. The order among the members in ablution is a Sunnah and not an obligation. Refer to: Majma' al-Anhar 1: 15, Fath Bab al-'Inayah 1: 56, Sharh al-Wiqayah p. 83, al-Wiqayah 56, and Bada'i' al-Sana'i' 1: 22, and God knows best.