The situation is that the account seems to have had the password changed, this is ninja's fault for not upgrading to a mojang account. That usually wouldn't be an issue, as you can simply reset your password provided you have access to the email account that you used when you created your Minecraft account.
This is not the case.
Ninja has lost access to the email account that was used to sign up to Minecraft and therefore cannot reset his password. To recover his account he required his transaction ID, another detail that was lost when his email account was hijacked/locked/deleted/sent to the moon.
The account seems lost, no matter how many people can vouch for his real ownership of the account, unless there is severe intervention and goodwill from Mojang it will be in some little script kiddies alternate account database for evermore.
By vouch, I mean some serious people, most notably a 51k YouTuber (DRLGaming) and a handful of other people.
-Puddleduck (P.S: Please help!)
This is the seemingly 'canned' response from Mojang support: (click to enlarge)