This company sells real human skulls. It claims all of its skulls are ethically sourced. How do you ethically source a human skull for sale to a random buyer?

No, I don't want to buy one. This came out of a discussion about my brother, who is so much weirder than me if you can believe it, who owns a real human skull.

I don't know how he got it. I don't know where he got it from, maybe this company, more importantly, I don't know why he would want such a thing. He is not a scientist, he works in IT. He did get an MFA in theater, wanted to be a professional theater director and loves Shakespeare, I can't believe the reason was because he wanted Hamlet to be super authentic.

We're not all that close, so it really hasn't come up in conversation. I only know about it because he posted elsewhere a while back that he was on a Zoom meeting at work and he showed it off and couldn't understand why everyone stopped laughing and got silent. So obviously he thinks it's cool to own it.

It used to be a person. I'm an atheist and I don't believe in an afterlife, but that's just basic disrespect.

Anyway... how can you ethically source a skull and then sell it on the open market?