As stated by another poster, this event never took place. It was based on a nightmare that Kovic had and told to Oliver Stone. Also, the incident in which Kovic claims he accidentally shot another marine is murky and the conclusion of his commanding officer at the time was that it was very unlikely that Kovic accidentally killed a fellow marine.

JDavisii is right. Kovic himself admitted he only did that in a dream, visiting Wilson's family.

But in real life ron never went to see the parents and tell them .

Unless it shines a light on friendly fire, which could reduce future accidents as such.
iiaaarrrggghhhhhhhh said jesus, trying to blend in!