Jason’s demise is followed by that of Freddy Krueger. Freddy with his “knife hands” seemed a little subtler. While not crucial (since he attacked during dreams), it will free kids of the 21st century from that 1980s terror.
Here’s an idea: analyze his dreams over a sufficient period, say, 30 days. If they are adequate, a doctor (particularly a neurologist) will administer Freddy an EEG, and they think it was congenital. Freddy gets an operation to replace his knife hands with 3-D printed prosthetic hands. And once he has officially recovered, he becomes human, like anyone else. Several years and/or decades later, he dies naturally. And there is now a truce.