You may have it exactly right, but we don't know yet. It could be that the dad burst in and started waving a gun immediately. I don't think all the facts are in yet.
Knowing that particular fraternity, I suspect the brothers were well primed and quite intimidating, but I wasn't there. Since graduation was today and all of the students went home, I probably won't hear the real scoop before next September.
There will undoubtedly be some alcohol related charges filed in the near future.
O/T...I like your homepage. :)