What are the risks from selling weed?

So ive been friends with this guy for years.just today he told me its about time i knew he sold marijuana.i was pretty shocked.he's an honor student,top 10% of his cl,marching band,very respectful....and he's a freaking drug dealer?!i didnt belive him until he showed me the freaking plants he had in a room specialy deisgned for growing.i told him if he was scared someone might get mad and go crazy or someone will pick a fight,he said him and his people are well armed,e showed me nothing but machne guns and bulletproof vests,e even showed me a grenade launcher so he said he was ready for war and that he only sold to people of good trust and not just any thug off the street.what are the dangers of selling weed?hes 16 btw