[Ger-Poland-Volhynia] Acquiring birth and marriage certificates

[Mike Glime]

Hello list,

A cousin in Germany has asked my help in trying to obtain his birth papers
and the marriage certificate of his parents.
The marriage occurred 13 June 1939 in Neu-Posen (Nepoznanitschi).
His birth was 16 April 1940 in the same town.

What options do we have in finding a copy of those documents by either
using him as a direct relation or myself as a non direct relation.

Thanks in advance,
Michael Glime
www.ermisfamilyhistory.com