He proceeded to besiege his uncle on behalf of the pretender imam, and forced him to plead for a truce.
Since he controlled San'a and the seaports, he was able to block the revenues of al-Mansur al-Husayn, who was ensconced in Shaharah and whose powers were rapidly dwindling.
When al-Mansur al-Husayn died in 1720, the Zaidi state was firmly in al-Mutawakkil al-Qasim's hands.
In the following year the Arhab, together with the Hashid and Bakil tribes, rose again, and tried to enlist the support of the imam's son al-Husayn.
Apart from his personal bravery, he was considered a generous character who spent much money from the treasury on the poor.