Mountain goats are generally peaceful but they are still wild animals and I was intruding on his territory in that picture. They are unlikely to resort to head-butting but they will definitely try to steal your food. As far as I know the greatest risk posed by goats is that they can dislodge rocks while they're poking around up high and when that happens any climbers beneath them are gonna get rained on.
I trust the man that did not know had a nephew
I'm actually not sure, I didn't know him that well.