A Y STR test does not assess "ethnicity" directly, although you may be able to infer his background if he shows a number of matches to people from a particular region. You might get some information from a Y SNP (haplogroup) test or an autosomal test, however, since you cite European populations, they can be quite imprecise because of the considerable population mixing in Europe over the centuries.
Before selecting a test, you may find it helpful to review this guide:
https://sites.google.com/site/wheatonsurname/beginners-guide...