This doesn't make sense since when recovering an account he would need to change the password, and you wouldn't have access to the account because he wouldn't know your password. That email on the account also doesn't match any records we have.
As other users said the darker UI is from an older client versions, it won't be coming back. Skins will also probably not be implemented, it's not a beneficial feature to the functionality of the client so it's not really important to have at all.
Looks like he hasn't been online recently but I did alert him of the dispute and put him in TWC, we'll wait 24 hours to see if he resurfaces and can provide an explanation.
Try using a Windows 10 VM with Parallels or try setting up Bootcamp on your Mac. Bootcamp would probably be your best bet. Lookup both and decide what works for you, like I said happened for me so I definitely think its a Mac problem right now.