To Trisher: the boy could not have received the money under age 18 unless his parents gave a receipt for it and gave it to him, which was not a great idea. My rule of thumb is, "the more noughts on the end of the cheque, the older they should be when they get it."
These, and similar situations, like a child getting divorced and half her inheritance going to your future ex SIL, or a beneficiary being bankrupt and their share going straight to the Official Receiver, or losing means tested benefit, substance abuse or gambling addictions are what discretionary trusts are for. These make a Will more expensive, but give you some control over your money from beyond the grave!