I have two different accounts from different sources about Cole Younger interceding to save the life of a wounded enemy after the Lone Jack fight of 16 Aug 1862.
In Miles' 1970s "Bitter Ground" pp. 172-4 she relates the story of wounded Yankee Nicholas Erhart who Cole allegedly recognized as having helped the Youngers fight off jayhawkers some time in the past. The story goes that Cole had the wounded Erhart taken to a nearby home where he would receive better nursing and sent for Mrs. Erhart on Deepwater Creek, Rocky Ford in Henry County to come get Nicholas. Sadly, Mrs. Miles did not give her sources in this book, making it difficult to fully evaluate the origins of this story. I didn't take the time to find Erhart's military record, but Nicholas appears in the 1860 census where the story says he lived.
The second source is page 25 in the 1906 memoir of Quantrill's later adjutant William H. Gregg. Gregg maintained that Cole saved the wounded Major Emory Foster and brother from recrimination after the Lone Jack battle. Gregg was present just after the Lone Jack fight, and I have found Gregg to be accurate on details of other incidents he mentions. This tends to back up Cole's own 1903 memoir on pages 28-29 where he includes a postwar letter from Major Foster to a judge in Minneapolis.
There seems to be a good chance that both stories are true.