yes he can,,if he knew that the 15 year old driver was without licence and insurance and that the vehicle belonged to the boy father ,,,he commits the offence of ,,,,Allowing to be carried,,,
I would think that the father of the boy did not know and did not give permission to the boy to use or drive the vehicle hence the boy is guilty of ,,,taking a motor vehicle without consent,,,(he stole it)
so you are both guilty of the said mororing offences,,,,,,,,,,
if he is stoped by the police they will both be arrested,,,,s12 theft act,,