In this case it is just a matter of asking him if he needs assistance heading back up. This learner will know how he would like the rescuer to assist him. Usually you would just get the handle on the back of the kiters harness and haul him back up wind.
In a case of a loose kite, always grab the centre of the leading edge of the kite. Thats the biggest bladder at the front of the kite, never the bar or any of the strings. place the kite down with the leading edge firm on the ground facing down wind so it flattens the kite, Put something heavy or hold it until he/she can come and retrieve the kite. Or deflate the leading edge by pulling the deflate plug and then detached his strings. This will always be appreciated with a simple thank you or he/she will definatelly pay for the next round.
In a case of a person getting dragged or lofted, asses the situation and if possible grab a firm hold of him/her, grab his/her handle on the back of his/her harness and ask him/her where his quick realease are. Or if he/she is unconcious, detach him/her by releasing him/her from the loop that holds him/her to his/her harness. This may use a little strength. a responsible kiter should wear a quik realease and a safety leash. At this stage you will be his/her hero and friend for life.
Thanks for taking the time to read this, I hope that you would never have to be put in such a situation. But you re 100% right always asses the situation and stay a min 50mts away from a kiter in strive. Dont circle around him just incase he has no choice but to let go. Dont swear and call him names because you are not solving anything. Stay cool and offer assistance and you will find a great friend that will return the favour one day. Cheers fellas Take it breazy!!