I think saying nothing can be very hurtful at the time to the bereaved, as if their loss is contagious or something - further isolating them at the worst possible time but it is probably preferable to saying really hurtful or heartless stupid things :) it's so hard I guess, if you haven't experienced it, to know what to say. Even if you have, it's hard to now what to say, but you just tend to 'know' better than most that sometimes you don't need words at all, just a look, or a hug, or a kind gesture- can mean so much more than a polite 'sorry' etc 