I ran into him yesterday while testing my addon. I wasn't going to keep the save anyway, so I let him beat me up. My PC is in the neighborhood of level 20 and it seemed like I took no damage. So I used a console command to set damage resist to 10. It still seemed like I barely took any damage. The first time I encountered Sneake, it seemed like he was more dangerous as I needed a lot of stimpacks. It was still great listening to the combat dialog and the aftermath of loosing the fight.I think his faction settings might be a little wonky still.
@Kefke_Wren once again, a great character!