chapter 4, he was molested by his uncle?

No uncle is a term u use with someone much older than u and seem to be close to

1) Technically, his cousin. As per page 5.
2) Uncle tends to refer to any man over the age of 30. It is a term of familiarity and some sort of affection, so you couldn't use this with, say, your boss. Would be alright with old friends of the family (parents' friends, neighbors).