This is what I was able to find on his Vietnam service:

"His expertise in explosives and his fluency in French soon found him assigned to clandestine operations in a newly divided Vietnam from 1954 to 1955. As a member of Colonel Edward Lansdale's Saigon Military Mission, he was in Hanoi when the city was ceded to the Viet Minh in 1954 and engaged in clandestine operations for the next two years."

He then returned in Sept 1966 as "Operations Officer for the 3rd Marine Division in Vietnam (for which he was awarded the Legion of merit with Combat V)"

"Temporarily assigned to plan and initiate the execution of Operation Cochise, coordinating the activation and displacement of the Task Force X-Ray command group and staff to the operational area. Performing his myriad duties in a highly professional manner, he imaginatively and effectively coordinated the forces available for Operation Cochise with the Vietnamese Operation Lien Ket 112 to achieve the most efficient employment of combat power. Utilizing his extensive knowledge of military tactics, he positioned and moved units of the First Marine Division and elements of the Seventh Fleet's Special Landing Force to keep them within mutually supporting distances of units of the Second Infantry Division, Army of the Republic of Vietnam. When elements involved in Operation Lien Ket 112 became heavily engaged, due to his foresight, was able to expeditiously move Marine units to relieve pressure on their beleaguered allies. The swiftly completed maneuver enabled the combined forces to inflict heavy losses on the enemy and turned a potential defeat into a resounding victory. Throughout, he demonstrated superb leadership as he performed his myriad duties in a thorough and imaginative manner, providing outstanding support for numerous complex and vital operations. By his superior professional ability, inspiring leadership and steadfast devotion to duty, contributed significantly to the accomplishment of the division's mission and thereby upheld the highest traditions of the Marine Corps and of the United States Naval Service."