Your best possibility for locating anyone who served with him is the divisional veterans' association. The address is:
30th Infantry Division Association P. O. Box 886 Spartanburg, SC 29304-0886
You might want to inquire as to the status of the 120th Infantry Association - an organization of individuals who served with the 120th Infantry Regiment during the war.
Veterans associations, being private concerns, can usually provide info only on those who are (or have been) members of the association or who have been in contact with the association for one reason or another. An increasing number of associations have been scaling down or disbanding altogether as the old timers fade from the scene and memberships decline.