No you are not irrational at all. Keep an eye on him and better if you tip him off to the authorities so he lands on some watch list. Not shaking hands with females is a sign that he's become DEEPLY fundamental and it only would take him just a few steps up the Islamic ladder to reach the Jihadi level and starts viewing the world into two dominions; Land of Islam "دار الاسلام "and Land of Infidel "دار الكفر"