Help: Father adopted (possible carribean ancestry?)

My paternal grandmother was an army med specialist (from AL) and paternal grandfather (from KS) was in the Air Force during the Vietnam war. They met and my father was conceived. Fast forward to this year and my dad finally agrees to take an ancestry test. I just want any input that may help piece together his tree. The heavy British influence and trace regions of the Netherlands, Spanish (father) and Italian (mine) make me think he really does have Caribbean ancestry. My mother’s ancestry results didn’t show any of these regions. Thanks!