According to his fan club, he pronounces it as in 'fries' - which is wrong, but common. Since it is German, the family name originating in central Germany, it is correctly pronounced 'grease'. Two possibilities come to mind: someone in his lineage got tired of hearing it wrong, and just went with the 'fries' version, or he's Jewish. The Jews tend to reverse the pronunciation to not sound German; e.g., Goldstein, (steen). Recall Young Frankenstein? In the end, it's his name, he can pronounce it 'Henry' if he likes. BTW, my name is Jonathan Gries, and I do know the family/name and immigration history.