son R . The Veteran is competent to testify regarding her experiences of having a conflict with her superior officer in service and of seeing the possible remains of a fellow service member who committed suicide . Jandreau v . Nicholson , 492 F . 3 d 1372 , 1377 ( Fed . Cir . 2007 ) ; Buchanan v . Nicholson , 451 F . 3 d 1331 , 1336 ( Fed . Cir . 2006 ) ( lay testimony is competent to describe observations , but must be weighed against the other evidence of record ) . Lay witnesses are also competent to opine on some questions of etiology , and the Board must determine on a case - by - case basis whether a particular