My grandfather doesn't know his heritage...?

I�m sorry to tell you that neither the name Willis nor Lawson point to a German heritage of your grandfather, if they weren�t written in a very different way in the past. The Name Wille f.e. is rather common in northern Germany, and there are some Larsons, too, whose ancestors actually were Scandinavians. Well, of course there may still be the possibility that the guardians of your grandfather changed his name to make it sound English. German names were unfavourable during the times, when he was a child.