I took kayaking classes before ever going kayaking in the ocean. No one in my class was able to rescue someone else from the water, something our instructor made us practice every single class. Instructor would tip someone over. We were on flat water in a harbor, no real current. But, most of the time, the would-be rescuer fell out of their kayak as well, which is what the instructor was trying to teach us (we were all wearing life jackets, of course).
Half of us could not get back on our kayaks without help from the instructor (who held the kayak steady from the opposite side the person was trying to climb). I was able to get back in my kayak, although I felt very shaky in this skill and it was a bit embarassing (we women had a harder time pulling our bottoms out of the water - the men had greater upper body strength). Most of the women had wider kayaks (which are less tippy). Being me, I wanted the tippy (faster moving) one, and it was HARD to get back in, and I felt really silly with my butt in the air while I performed my self-rescue, but I did learn to do it.
I would *never* be able to rescue a person in the water from a kayak, unless the water was shallow enough for me to hit bottom with my own feet - and I would never go kayaking with people who weren't wearing both life jackets and an insulated rash guard - even in 70F water. If I saw someone else in distress, I'd be screaming for help, but I do not think having two people drown would be the best outcome - and that's likely what will happen if there's not someone who knows what they're doing.
If there were two people in the kayak and one went overboard (and could not get themselves hauled back up onto the kayak without tipping it), it is a recipe for disaster if neither has a life jacket. One approach would be to get closer to the drowning person and have them hang onto the paddle - but in that case, the kayak can't be paddled and that's dangerous. I wonder if they had a towel or any other item to use. I'd use a bathing suit, if I had to, to keep the person next to the kayak - until rescue.
If both people were pretty experienced in choppy water kayaking, they could probably work out a self-rescue, but it would have to be quickly and carefully planned. IMO.