You can't make him share your views without tight reasoning. You can be his brother. At 15, he's going to be coming into sexual feelings if he hasn't started already, and that cognitive dissonace means that he'll perhaps be more receptive to hearing you out.
And yes, reject any bigotry he shops immediately, unless you want to hear it more often.
And yes, reject any bigotry he shops immediately, unless you want to hear it more often.
