It wasn't that Jasper couldn't handle, it was more that he couldn't handle him without hurting him, hence his plea for help. Jasper wasn't going to hurt Eli just to be free of him. When Shannon gave him enough room by removing Eli's arm, Jasper slipped away to sit outside of Eli's grasp to see how Eli would respond.

Not surprisingly, Eli didn't seem to approve of the warm fuzzy thing disappearing and moved his arms, bumping in Shannon accidentally with one. Finding another warm thing in the warm fuzzy thing's place, Eli did the first thing any sleepy child would do and immediately latched onto Shannon instead, attempting to draw him closer due to how warm he was. As drained and exhausted as Eli was, it meant that most of his body heat was gone, his body only keeping the important bits running when he was this low and ignoring anything non-vital.