Your brother's right -- though people certainly can survive severe throat injuries, it's still a relatively good bet. Plus, it's soft and easy to cut, so you don't have to worry too much about strength. Generally I'd recommend dragging it all the way across the throat to do maximum damage.
[considers] Other than that if you have finer targeting skills, I'd suggest through the eye up into the brain or between the ribs into the heart, but that's harder if you're not used to it.