Livre d'Or

Hmmm... "a way of expressing values" - yes, course, and to that extent I guess he's right that ethical choices in personal consumption work as a kind of internal ribbon-wearing, a way to assert (to oneself) that one is a good person. But I think he's looking too high when he dismisses such choices as being of no effect. Of course they're of effect - the meat industry is feeling the effects of rising vegetarianism. Ethical chocolate-buying hasn't done much yet to crush child slavery, that's true - but it has taken it to the point where plantations are closing ranks and hiding information about conditions on their farms - i.e. they're on the defensive,because they feel the push (tiny as it is).

To take a not-ethical example, there's the anti-vaccination movement. It has spread in the same way as many ethics-based campaigns, that is, outside government or professional circles, person-to-person; it is now having some clear (small, but visible) impact in disease outbreak, as in the current rise in measles in the US. Individual unorchestrated decisions do have effect.

Not the quick, over-powering effect that legislation can have (I'm not sure what your brother is suggesting as a way to bring about change, but that's one route, obviously) but still, effect.