"Mixing sites" are scams because you trust third parties with your data and with your coins
Stop spreading false information. Mixers are not scam. He can use a reputable mixer. It will have onion link and he should use Tor to access the onion link. I will not say that you do not know what you are saying because you know about this very well, so I will say you should stop lying.
I would recommend a mixer that is open source and reputable. If you can not check how the mixer is working you can definitely get scammed even if the mixing service is reputable. There are also a lot of "reputable" exchanges that suddenly closed and scammed a lot of people. So better to do some research and mix only small amounts from time to time.
To say that mixing services can not be shady is kind of shady in it self.
Who is saying that a mixer can not be a fake mixer or a shady mixer? I did not see where I mentioned that. All I said was that a reputable mixing service should be used and that if you want to use the mixing service, that it is good to go for the .onion link which is more privacy that using the clearnet link.