Answer:
1. Because they enjoyed hearing his stories.
2. Because he thought people would make fun of an old fashioned Native American person or think he was weird.
3. Martin didn't want to wear the medicine bag because he was embarrassed by it. (You'll have to answer the second part of this question for yourself.)
4. Martin's friends reacted with awe and respect to Martin's grandfather. This was not the reaction Martin expected, as he expected them to be shocked or uneasy around him.