Valdr of the Moss Mother Cavern quest, Hunter and Hunted.

I find him wounded and have a brief conversation. I either give him a healing potion or cast Healing Hands on him, and he thanks me. Then I offer to help him clear out the cavern. He thanks me profusely, stands up ... and attacks me.

Clicking on him in the console and using setrelationshiprank 1 doesn't stop him attacking me. Neither does resetai. Neither does addtofaction 5A1A4 1.

Is there any way to stop this lunatic from being hostile for no reason so I can properly proceed with the quest?