Motorbike engine

My son has autism and he has been saving for a few years to be able to buy his own motorbike and when he could we had a nightmare of a time as the bike was delivered and the engine had a loud knocking sound and when we had it looked in to we was told the engine crank was snapped and some of the cogs was damaged and there was a hole in the piston and tapets where bent so now where trying to raise funds for a new engine as he loves to work on his bike and to be able to ride with groups and meet new people and make friends and find a job around motorbikes many thanks for reading