If there is some secret in PM and it is Craig Wright, who has broken into it, then he has already looked into it.
But, it is good if the current operator clearly says who he/she is.
I think it should be bloked imediately, if they don't we are under attack by a potential Hal/Hal family impersonator. Block the account and then if it's really someone from Hal family that has the password, they can easily contact theymos in reddit or something and prove it, until then the safe thing to do is to block it imo.
I hope Hal cleaned his PM story.
The problem is that we know it's not the case, the password has been changed today!
https://bitcointalk.org/index.php?topic=1787466.new;topicseen#new
I think it's a hacker for sure. The passwords were sold, probably on the deep web or something. Hackers make a lot of base by selling databases of hacked forums in big and pricey bulks, since some of the accounts may be from vip members, in this case Hal's. So yeah, most likely it's a hacker and blocking the account as soon as possible is the correct thing, but if he had valuable PM's.. the damage is done.