Small group of paddlers at the put in…looked, well…inexperienced. I advised the group that there is a low head damn as the FIRST feature on this river. At certain levels, it can be an issue for rec boaters / inexperienced paddlers. It’s deceptive. The victim is this report chose not to wear a PFD. Upon approach to the broken up low head damn, victim back paddled…this initiated his role over. This was a recreational kayak, no skirt, victim was immediately out of the kayak. Victim immediately was pulled under and struggled to resurface. We were R2ing, we began a trajectory toward the victim. He continued to to hold his paddle, I shouted “SWIM, Let go of paddle and SWIM!” This helped a bit, but the victim was not swimming aggressively. More of a doggie paddle. I followed that command with repeated, SWIM, DO NOT STAND UP. The victim repeatedly did not swim, he kept his hands below the surface, either doggoe paddle, or an attempt to grab the bottom. In addition, this individual tried to stand, back facing upstream, over and over. Each time, he was thrust forward, face first, back into the water. At this point we had almost caught up to the indivudual, a paddle rescue was attempted. The victim did grab on to the t-grip, my paddle partner pulled him to the boat. He failed to grab the safety line, and at this point we were in front of him(downstream). We drove him river right, where he caught a small eddie, and made it to shore. My partner and I recovered his boat, and PFD. We made certain that he made it to his boat and group. I made certain he was wearing his PFD before we left. VERY CLOSE CALL.