Play dumb to an extreme level. Always insist the things don’t work.

If he asks you to share a screen so he can help, say you don’t know how. Every time he gives you a new instruction, make sure to misinterpret it just enough to make it seem like you are trying to listen, but completely failing to understand.

Ask him to send you $50 via PayPal, but refuse to give him your PayPal account. Tell him nobody else has ever asked you for that when they have sent you money

I’m not saying all of this is a good idea, but they are examples of how you can mess with somebody like that.