Would you use tú or usted when speaking to: your best friend? your doctor?

Read the excerpt from "the scarlet ibis."within a few months doodle had learned to walk well and hisgo-cart was put up in the barn loft (it's still there) beside hislittle mahogany coffin. now, when we roamed off together, resting often, we never turned back until our destination hadbeen reached, and to pass the time, we took up lying. from the beginning doodle was a terrible liar and he got mein the habit. had anyone stopped to listen to us, we wouldhave been sent off to dix hill. what does this passage foreshadow?