I'm wondering when LE is going to arrest him? That is when Athay can start working with MH. I'm sure he and the professionals at the hospital know what's up with him. Those outrageous lies cannot be ignored. Athay needs to consult with independent psychiatrists in order to deal with his client. I'm sure he has a lot of experience in the legal field, but dealing with this guy is going to be the mental equivalent of catching a greased pig.
Mabelkitty mentioned the possibility that he is homosexual. I'd love to find out why he was supposedly shipped home early from that mission.
The obvious stance would be that he "wasn't himself, something inexplicably took hold of him," and he blacked out on the essential facts of the killing and its aftermath, ie. what triggered it, how it was accomplished, and much of what he thought and did afterward, except suddenly where that body is and perhaps how he got to that location. So he's now able to give them the body and at least an implicit confession only because of this delayed and unexpected "flashback."
Jekyll and Hide ring a bell?
This way he not only side-steps death row, but most importantly, does not have to admit to any of his lies about Lori and does not have to give up his sense of being in control of others. IOW, he gets to represent himself as a hapless victim who simply got caught up in the relentless grip of something he couldn't resist or even remember, thus preserving his identity of deceiver and manipulator, while also "defeating" the prosecutor and the hangman alike -- and, of course, it was all his own brilliant plan. I believe Hacking could accept that outcome if the gravity of the case against him appeared to warrant it. But Athay and the prosecutor must condition him for all this well in advance, starting now.
I can't speak to the conjecture about his sexuality.