Loans, Custodianship, and Damages

A man is at a bus stop, where he sees a boy that he knows from his neighborhood. The boy tells him that he misplaced the money he needs for his bus and asks if he can borrow $20. The man happily agrees and lends the money to the boy. When the man sees the boy a few days later, the child avoids him and makes it clear that he isn’t planning on paying him back. Does the boy have to repay the loan?

I was shopping in a grocery store with my child and noticed that he had helped himself to something that he had taken off the shelf. Do I have to pay for what he ate?

Somebody arranges a neighborhood carnival to raise funds for tzedakah. One boy is given the job to take the money and give out the tickets. After a while, he gets bored and walks off, and some of the money goes missing. Is he obligated to pay for the lost money?

A father calls up and says, “Your son started a fight with mine for no reason and broke his glasses. You have to reimburse me for their cost.” Does the other parent have to pay for his son’s damages?