More flaming horse s#!t. The Constitution is silent on the topic of dual nationality. It only requires that he be a natural-born citizen.
Not the constitution, but security clearance.
Please read the DoD’s stance on security clearance with dual citizenships.
http://www.dod.mil/dodgc/doha/isp.html
Actually, the DoD is my only hope for this mess and if there is something there, they will uncover it while researching for the level of security clearance he needs.