Since the only two times that Ju Peter has shown visible concern, with noticeable sweat, were in relation to Shanks and Garling, it might be something about the Figarland Family as a whole that worries him.
Ju Peter's Abyss number is most likely 1, while Garling has probably taken Saturn's 5. But as the crescent moon, Garling should become the closest to Imu. Maybe a betrayal will occur then.