Her actions make the witnessing work look a sham and an excercise in reporting hours only. It also puts their morals into question.
If a parent found that their child had a dangerous toy given to them by a friend they would want to warn the other child's parents. If it was a matter of not wanting your child to have a particular toy you would have him return it to his friend or if the child was very young you would do it yourself. It could have been a good opportunity for his mother to explain that they were JWs and what their beliefs were. It is the responsibility of the parents to safeguard their children from what they consider any dangers but she has thrust all responsibility onto Caleb.
To make Caleb put it in the bin was very cruel. His friend will wonder what happened to the toy and he will have to say he threw it out rather than his mother took it off him.