I don't understand.
How can someone steal bitcoin with a simply hack of an email account?
Can someone explain me? Did you have some passphrase or something in your email?
If I am not mistaken his account on a exchange was hacked due to the email. So he wouldn't have a private key since it was on a exchange.
as far i know, exchanges only need verification link confirm when doing transaction withdraw/sending.
but, i would be same curious, how this hacker can get all of your information, include both email+password and Bitmex+passphrase at sametimes.
Are you sure this is not your brothers or friends which can have access to your computer?