Anyone who has become an heir must decide whether to accept or reject the inheritance. If you do not want to accept an inheritance, you can declare your rejection of the inheritance to a notary, have it certified and submit it to the probate court.
If someone got married abroad, an application can be made to the registry office of their place of residence for the marriage to be subsequently recorded in the German marriage register (the family register on application no longer exists since 01.01 ...
Civil status documents are generally not allowed to be authenticated! Certificates are to be newly created. Please contact the registry office that issued the original certificate.