Good job, I think, it's more interesting if you explain about bitcoin to your friends by using a laptop, you can make slides about bitcoin, and you can also prove the contents of your digital wallet to him. it will make him believe that bitcoin is not a scam. this is my experience when explaining bitcoin to my friends and my family.
I think it's a bit exaggerating making a slide about bitcoin for the reason that you want to justify that bitcoin isn't a scam. A simple conversation is enough to educate people about bitcoin and explain how it works. But in OP's case, His friend is a scam victim and you need to put a different approach for him to believe that bitcoin isn't a scam. We can assume that the scam victim will be hard to convinced due to his experience but some persuasion can change his mind. You can somehow explain the reason why did the victim get scammed and how to avoid it.