Millions of military veterans struggle with post-traumatic stress disorder (PTSD) when they return home from a deployment. Now, one of these veterans has written a children’s book to help his daughter understand his PTSD.

Army 1st Sgt. Seth Kastle spent sixteen years serving in the Army Reserves, and during that time, he had deployments to Qatar, Afghanistan, and Iraq. After all these years of service, Seth felt an anger inside of him that nothing could make go away. He would often have outbursts that he could not control, and he had no idea why they were happening.

Seth had no idea at the time that he was suffering from PTSD, which can manifest itself in numerous ways, including anger. That’s why Seth was having those outbursts that he couldn’t control.

Seth’s PTSD went untreated for years, and it began affecting his relationship with his wife Julia.

“I waited until it was too late,” he said. “There have been a thousand times looking back where my wife should have left me.”

Julia, however, refused to give up and they eventually found Seth treatment that worked.

Seth had no idea how to talk to his little daughter Raegan about his PTSD. After one particularly difficult workday, Seth returned home and wrote a quick story about his PTSD. This story went untouched on his computer for quite some time until Seth heard about another veteran who had published a book. That’s when he decided to turn his story into a children’s book that could be used to help other military families.

In 2015, Seth published “Why Is Dad So Mad?” which tells the story of a family of lions who fight to overcome the father lion’s PTSD. The book did wonders in helping Raegan understand her dad’s struggles with PTSD.

“After I first read the book to my daughter, I remember her saying, ‘I’m sorry you have a fire in your chest now, Dad,” Seth said. “She was four at the time. That’s something I’m always going to remember.”

“No matter what, when they’re mad or sad at you, they still love you,” Raegan wisely explained. “There’s always a fire in his heart, but no matter what, I know there’s love.”

Seth has gone on to turn this into a series with the new book “Why Is Mom So Mad?” He has also had a second daughter with Julia, which made him even more determined to make a difference.

“I hope that other military families have a chance to sit down and explain to their kids that it’s not always going to be easy, but they’ll get through it,” he said.

Find out more about this in the video below.