Tom is imperious and has little regard for the feelings of others. We see this in Tom's rather rigid treatment of his friend Huck and also in his indifference to the suffering of his aunt during the period of Jim's planned escape.
Huck does consider the feelings of others and agonizes over them. He is not purely empathetic or sympathetic. He acts selfishly and cruelly from time to time, but he demonstrates these positive qualities on several significant occasions.
Warnging the Wilks family about the King and the Duke is one place where Huck shows his ability to understand the feelings of others. Also, his choice to help Jim escape from the Phelps farm serves as an example of Huck's empathy.
Huck does defer to others to a considerable degree as well. This is something Tom never does. In Huck's willingness to be led, he acts in ways that he regrets, hurting people's feelings or doing wrong because the King, the Duke, or Tom has told him to do so.