Complex sentence: Braun returned to his family's manor in East Prussia and was active in several agricultural organisations like the Raiffeisen cooperative, in 1930 he became the Vice President of the "Reichsverband der Landwirtschaftlichen Genossenschaften" (Association of agricultural cooperatives).
Split into simpler sentences: Braun returned to his family's manor in East Prussia and was active in several agricultural organisations like the Raiffeisen cooperative. In 1930 he became the Vice President of the "Reichsverband der Landwirtschaftlichen Genossenschaften" (Association of Agricultural Cooperatives).