There is a brief family tree for Charles B McLean on ancestry.com
It says he was born on 1 July 1919 in Illinois.
He graduated from Hillsboro HS, Hillsboro IL, in 1937.
I found a newspaper article in the "Decatur Herald" from 3 September 1942 which says that Charles B McLean of Hillsboro, son of Ben O McLean, was to become air cadet in the Army Air Force. On the ancestry message boards is one message which says he was in the class of 44-A and shows up in that class book for Bruce Field, Ballinger, Texas.
He does not appear at all (at least I could not find him) in the 1946 book about the 79th FG. Maybe someone else can take a look. These early books were done without word processors or computers and it is not unusual that people and events were missed. The whole book is online here:
https://archive.org/details/FalconCo...Forces19421945
In the brief family tree on ancestry, the final entry gives his death on 22 Sep 1944, Blois, Loir et Cher, France. I have no idea where that information comes from (or if it is even correct).
I believe the 86th FS, (or at least parts of it) were operating out of a base at Lyon around September 22. The whole 79th FG was about to move back to Italy. They had moved to France in late August from Italy.
There is no MACR that I can find for McLean the fighter pilot. There is a MACR for McLean the gunner but that is a different person.