You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Genghis_Khan

Context:
Jochi died in 1226, during his father's lifetime. Some scholars, notably Ratchnevsky, have commented on the possibility that Jochi was secretly poisoned by an order from Genghis Khan. Rashid al-Din reports that the great Khan sent for his sons in the spring of 1223, and while his brothers heeded the order, Jochi remained in Khorasan. Juzjani suggests that the disagreement arose from a quarrel between Jochi and his brothers in the siege of Urgench. Jochi had attempted to protect Urgench from destruction, as it belonged to territory allocated to him as a fief. He concludes his story with the clearly apocryphal statement by Jochi: "Genghis Khan is mad to have massacred so many people and laid waste so many lands. I would be doing a service if I killed my father when he is hunting, made an alliance with Sultan Muhammad, brought this land to life and gave assistance and support to the Muslims." Juzjani claims that it was in response to hearing of these plans that Genghis Khan ordered his son secretly poisoned; however, as Sultan Muhammad was already dead in 1223, the accuracy of this story is questionable.

Question:
Who did Jochi reportedly enlist to help him stop his father's massacres? 

Sultan Muhammad