He's his own person. You want to help him avoid future headaches and protect his privacy but ultimately, he is his own person who should be able to make his own

He's his own person. You want to help him avoid future headaches and protect his privacy but ultimately, he is his own person who should be able to make his own choices. Understandably this is difficult for you since you are being asked to buy the new laptop and have valid reasons for not wanting to purchase one with Windows but none of that changes the fact that he is his own person with his own thoughts. You may feel complicit in any trouble his choice brings him since you're involved in the purchasing process but that's on him, not you, if it ends poorly.