Eragon Theme of Friendship

The great metaphysical poet John Donne once wrote, "No man is an island." What he meant is this: nobody goes through life on their own. In Eragon, this is definitely the case for our hero. Though he faces down Shades, Urgals, and lots of other baddies, Eragon always has peeps in his corner to help him win the day. They range from a blue dragon, to an old warrior, to a skilled swordsman with a mysterious past. In every case, their friendship with Eragon goes to show that even the most heroic among us must depend upon the support of our closest pals.

1. How does Eragon's lack of a father growing up affect his reliance on the friendship of others?
2. Is Brom a good friend to Eragon? Or are the lessons that he delivers done out of a sense of duty?
3. Does Murtagh fight with Eragon for friendship? Or does he have other reasons? 
4. Is Eragon right to question his friendship with Murtagh when he cuts off the head a defenseless man? 
5. What do you make of Saphira's jealousy of Arya? Does she see her relationship with Eragon as a friendship or something more?