Recess is 15 minutes - it takes about 1 -2 minutes to walk out there. At most he played for 3 minutes..no he doesn't walk home nor does stand outside to wait for a bus. Genius, I wrote that I am dealing with it - not ignoring it. Obviously I am not making a big deal out of it - asking that he not stand in sun is reasonable with heat triggered asthma.
Sorry but again I think your child is playing you as a fool. Obviously HE DOES NOT CARE ABOUT RECESS or he would stop the talking out. You are giving the child excuses for why he should not be punished the same as other children are. My daughter stood in the sun as well for her WHOLE recess 5 days in a row due to recently having surgery (which by the way she had an asthma attack on the operating table while they were tubing her and they had a hard time getting her to breathe) and it did not bother her. She was not happy about being stuck with the kids who could not follow the rules (her words) but she survived. We have the exact same weather and temps as you since we are one state over.
I stood in many formations at Fort Bliss Texas, Ft Jackson SC, as well as here in the 100 degree temps and am here to tell about it. Also did PT in the same type of weather and temps. You are being way too dramatic but then again I am still seeing you do not feel his disruptive behavior should be punished and that a slap on the wrist is all he should get. My daughter is in 1st grade and even she knows there is an appropriate time for talking and she will tell kids like your son to be quiet if they are talking when she is trying to learn. My now 11 year old had the issues of yelling out the answer and talking but no excuses were made for her. She was told to stop and she knew the punishment.

The kids at our school have to sit on a bench if they miss recess, in the sun.
I'm glad this kid isn't in my district because by the time he gets to high school he will think he's untouchable by teachers for discipline purposes.