One day when Ollie's parents left they never came home.
Do you think that it was Ollie's fault?
Yes, they said he was a trouble maker.
It's extremely wrong to abandon a child since a child cannot take care of him or herself and one can get into legal trouble if caught doing so. If you know that a child has been abandoned, you should contact the authorities so the child can get the help he or she needs and be placed with someone like a relative that can take care of them.
Someone gave him away, so he can't be abandoned.
Unless there was a legally binding agreement, then they did abandon him. The people who took him have no legal obligation to keep him or care for him. Ollie could be in a dangerous situation, and it would be responsible to report it.