Maybe they could float a reality tv show of him at Pelican Island
sharing a cell with a couple of two hundred eighty pound gang members who hate baby killers. ( ..." NO BUHBUH PLEEEEEEEASE, NOT THE SHOVEL HANDLE AGAIN!)
If things are handled properly, a person sentenced to a mental hospital can remain there longer than a conventional prison sentence. I doubt this would apply in his case though. He could be confined/treated till sane then tried.