Maxim knew he had to listen to Renwyck, not only because the wizard knew the force of nature better than him since his dragons seemed to have special abilities to predict the weather, but also because Renwyck still could think straight.
Maxim was too frustrated and upset by everything that had happened to him and Emmelyn after they reached Myreen and found out the truth. Added to the fact that Emmelyn was in a bad condition, he sometimes felt like he was about to lose his mind.
So, he was glad that Renwyck was around him to give him good advice, to nudge him when he strayed, and to give him support when he felt like giving up and didn't want to go back to Castilse.
So, having listened to Renwyck's advice, Maxim asked the coachman, Jon, to drive faster so they could reach the city in front of them as soon as possible.
Before they entered the city gate, he told Renwyck to let the dragons go and rest in a place where humans wouldn't bother them.