Magellan did not show concern for crew because in a journal of Antonio Pigafetta he says "...we only ate old biscuits reduced to powder, and full of grubs, and stinking from the dirt the rats had made on it when eating the biscuits, and we drank water that was yellow and stinking." Eventually some of the crew member were immune to scurvy.
He had really good Navigational skills because in "Over the Edge of the World", it says "Magellan even relied on the taste of seawater to guide the fleet. As the water became fresher, he knew he was traveling inland, and once it turned salty he realized he was approaching the Pacific on the western side of the strait.
He was dedicated to the task because in Over the Edge of the World it says that Magellan "he regularly sent small scouting parties in the long boats..." to see tell what is coming up ahead. So he does not end of going the wrong way.