Why does my 17 year old brother always act like a traumatized soldier?

well based on what u said he can play pretend all he wants but thats as far as he will get being all PTSD and giddy is a sure sign of mental instability..plus anyone who talks like that and hasent even done anything like that.... is a tool im a 11b getting ready for deployment and well ...my mouth is shut and my eyes and ears are open..telll him he can cram it till he does the man dance...till then hes just a little boy on a rant