If he's really german, I have to apologize on behalf of most other germans. (Some over here are stupid racists, but we're not in the 1930's anymore. I don't think the rate is higher than in any other western country)
If he's just someone who's trying to act funny, I really feel sorry for him. If he believes that germans aren't capable of any english grammar or orthography, he actually never could have talked to one.
It's not a matter of colour or ancestry...either you have game or you don't...