Possible viking in Louisiana?

My dad recently did his ancestry DNA test. Actually a family friend ordered it for him and she hasn't brought him the results yet but he says she told him he is 78% Northern England. I tried to research what that means. I understand Viking isn't ethnicity but the DNA can lean to markers showing this historical connection. From what my search results suggest, his ancestors have a high likelihood of having been viking. Firstly, is this correct? We're also Cajun in Louisiana. How in the world did that migration occur? A possible viking in Louisiana? I'm not having good hits in my research into this possible history. Anyone can educate me please?