Hi from Paris,
Your father was right to keep these indisputable evidences of Nazi ideology and you are right with your wish to preserve them *.
In France, we have "the" answer.
What is the Jewish institution which will be our survivor generations after generations to study, research and transmit history and memories of Holocaust ?
This is Paris' Memorial de la Shoah.
In USA, USHMM in Washington is dedicated to same vision, as I could see when I visited some years ago :
My advice is to contact this institution.
Blayb gezunt !
Archives & history of Medem Center - Arbeter Ring (Bund / Workmen Circle / Skif of France)
* May I add that in France, Nazi items are unlawful to sale and to public exhibition, except in historical institutions.