I saved a bloke once. he was about 1km out and couldn't relaunch. the sun was going down and the seabrease was going to turn off any second. But this bloke wasn't fussed at all. I'll be right he said. any way i convinced him he wasn't and body dragged him back to the beach. took about 20 mins.
Good thing that you insisted.
Often kiters don't realize that if they have been ridding for a couple of hours they may be a bit low on energy and get hopelessly tired after swimming a few hundred feet.
When I offer help the answer is nearly always no thanks.... so I kite near by for a bit and offer up help again and insist that it's no problem and that it would make my day.
To give you an idea of how important it is to accept help or insist on giving it ... one guy I was dragging in got a terrible cramp about half way in. He said it was so painful he had to ditch the kite. I managed to get him back no problem, but had to chase the kite downwind and bring it in at another beach. It could have been nasty if he was on his own with that killer cramp.
Another thing that I like to do is ask if the kiter in need wants to self rescue and I offer to keep a close eye on him or her and take over if it does not work out.
Anyway my point is when offering help it's good to insist a bit.