How would I go about writing a letter to my parents if i were the sniper and trying to explain to them the situation and how I shot my brother?

I think that this depends to some extent on where you
think that your parents come down in terms of their political beliefs.  Do they agree
with your side, your brother's side, or neither.  In general, though, I would emphasize
a couple of things:

• I would emphasize how and
  why I think that my side is in the right.  I would talk about why I think that helping
  my side is important.  This establishes a reason for me being out there shooting
  people.


• I would then emphasize how sad I am and how much
  I did not know that my enemy was actually my brother.  I would tell them how I never saw
  the enemy sniper until he was already dead.  I might say that I would rather have died
  than kill him, but I did not know what was going
  on.

Overall, I would make the letter sound very
sad and apologetic.