Army Sgt. 1st Class Richard Stayskal felt like he was falling apart.

A physically fit Green Beret, Stayskal first noticed something wrong with his body in March 2017 while training at the Army's Special Forces Dive School in Key West, Florida. Unable to keep up with his elite training — a red flag for the athletic 37-year-old combat veteran — he was sent home to Fort Bragg, North Carolina.

By April, Stayskal began to wheeze and had difficulty breathing when lying on his back; other times, his body would go numb, and his vision blurry. In May, he visited the emergency room twice, once on base at Womack Army Medical Center and a week later out in town. Then, in early June, he began coughing up blood — a teaspoon at first, but it was more by the day.