But if it's with the consent of his parents you can go ahead, they still have the right to take decision for their son but the unlocking should be done in their presence (the parents) also following the legit way of unlocking the wallet.
I guess you are right and it was mentioned that op had explained to his friend’s parents what it was and what could it hold. I hope they understood it properly so that it doesn’t fireback towards op in the end.
They could be totally clueless about it and lose everything their son had worked up for. That would not only be a shame but also disrespect to the deceased, in my opinion.