I agree with your response to him. I find really odd how different DACs can sound different due to material. If he used the idea that DACs can have different filters that can change some stuff sure I guess!You such a funny guy!If you have such understanding, maybe you can use some of your knowledge of science and electronics to explain how DACs can sound different besides just saying it's due to the use of different materials?
Let's use sony for an example too!
Sorry for the giant screenshot. But sony is making a claim that because this player has a Copper Gold plated chassis. It has a "unique natural, acoustic sound".
But scrolling around it is still a Digital Audio Player. Digital music, 0s and 1s do not possibly understand copper and gold to create natural acoustic sound.