Buddy letters

Hello all,
I was curious to know if anyone has info on buddy letters for PTSD. My Pueblo doesn't even know what Pueblo is so he's useless. Is there type of format? Or need to include anything specific?
Thanks

 

[chaplaincharlie]

A letter TO WHOM IT MAY CONCERNED
from your buddy should suffice to help connect your injury/illness to combat/service connection.

 

[oddpedestrian]

Not sure why a buddy letter is needed for a MEB have you been diagnosed? if you are still active duty the link is already established.