Vietnam war Marine veteran Oscar C. Muñoz said he only takes a shot of tequila twice a year, and one of them is on Memorial Day.

“It is to remember all my friends who died in Vietnam,” he said. “It is a very sad day for me.”

This Memorial Day, May 25th at noon, Muñoz and many other local veterans will join once again to honor all the soldiers who didn’t come home at the Logan Heights Veterans Memorial, at Chicano Park.

There, most likely Muñoz will share stories from the book he wrote with the help of his brother, Jessey Muñoz, about his experiences in Vietnam, and the battles he has faced in life after coming back to the U.S. The book, Hidden Enemy. PTSD: A Puzzle Piece That Does Not Fit, was published earlier this year.

And Hidden Enemy has death all over it.

It starts with a recurring nightmare for Muñoz: He is inside his bathroom with gun to his head, contemplating suicide. It ends with a remembrance of his brother-in-law, Master Sergeant Rey Careaga, a Korea and Vietnam veteran who passed away in 2014.

“My whole book is Memorial Day,” Muñoz said.

But it also tries to help other veterans who are struggling with PTSD, post-traumatic stress disorder, a condition Muñoz has struggled with since he came back from the war, more than 40 years ago.

“War has many effects on a soldier’s mind,” he said.

Throughout Hidden Enemy, one can read about Muñoz’ life after Vietnam: He came back from a war abroad only find himself in the battlefield that his mind had become. PTSD and all that it entails had an effect on his life, especially his family. He went through a divorce, faced unemployment, and lived a period of homelessness.

Many times he contemplated suicide.

Muñoz said he was inspired to share his story when, two years ago, he read that 22 veterans commit suicide daily.

“In this book I tell about my personal experience with PTSD,” he said. “If by sharing my story, I can help just one veteran from committing suicide, then I would have accomplished my goal for writing this book. I wrote this book to express my feelings about PTSD in my life. I didn’t think that those sights and sounds would haunt me the rest of my life. As common with PTSD, you don’t just goodbye to war, you take it with you.”

In his book, Muñoz describes his experiences in a straightforward, but also poetic, manner. From his early life in the fields of Arizona to enlisting in the Marines, and then his time in Vietnam, to the 40 years since his return, eventually resettling in San Diego. He has since remarried, and with his wife Norma, he is very active in the community.

“My family and friends do not know exactly what I endured while in Vietnam but those memories are in my head,” he writes in Hidden Enemy. “I write this book so that I may voice my feelings and see my life on paper […] Living as a veteran with PTSD is difficult […] The battles that I fought are penned in this book. These are not the only encounters with the enemy that I had but these are the events that I am constantly reminded of when my PTSD consumes me.”

But on this Memorial Day, Muñoz said he will be proud to raise his beer and say Salud! in honor of his fellow brothers in arms at the Don Diego VFW -Post 7420, in Barrio Logan.

“A soldier can’t be more proud than going to the post, as a Latino, as a Mexicano, and have a beer, and have a toast with veterans from World War II, Korea, Vietnam, Beirut, Desert Storm, Iraq, Afghanistan, and have a toast in honor of all the veterans we lost in battle, all the friends we lost,” Muñoz said.

Hidden Enemy. PTSD: A Puzzle Piece That Does Not Fit is available on Amazon.com, where it has received many 5-star reviews.