@cbsnews: After Navy SEAL Ryan Larkin's suicide, his father Frank started hunting for answers. Ryan's death was attributed to mental illness, but Frank suspected his son's military service resulted in an invisible brain injury - a kind of wound unknown to science. A post-mortem autopsy found scarring on Ryan's brain, and there were similar results in the brains of other Navy SEALS who later took their own lives. The findings led Frank to push for change in the military – a fight profiled in Sunday's "@60 Minutes." "At some point, I’m going to see him, and I don’t want to disappoint him. He clearly gave me a mission," Frank told @errol barnett cbs on "CBS Morning News." Watch the 60 Minutes story on Frank's fight in the linked article. #veterans #military #navy