The father of American Sniper Chris Kyle has spoken  for the first time since his son's killer was sentenced to life in prison, in an emotionally-charged interview with NBC News. Wayne Kyle said he and wife Deby were 'surviving' now that they finally had time to process their son's death, following the end of his killer's trial. Chris Kyle and friend Chad Littlefield were shot dead at a Texas gun range in 2013 by Eddie Routh, after taking the troubled vet to the range to help him cope with his PTSD. In February, Routh was found guilty of the murders and sentenced to life in prison without the possibility of parole. Scroll down for video . Still grieving: Wayne Kyle, the father of American Sniper Chris Kyle, gave his first interview on Thursday since the end of the trial of his son's killer . Torturing: Watne Kyle told Lester Holt that it was difficult to attend the trial and sit in the same room as his son's murderer . Shooter: Eddie Routh shot dead Kyle and friend Chad Littlefield at a gun range in 2013, after the pair took him shooting to help him with his PTSD. Routh, pictured center in court in February, was sentenced to life in prison without parole . American legend: Chris Kyle (pictured) served as a Navy SEAL for 10 years and during that time became the most lethal sniper in U.S. military history. He wrote a book about his military career titled 'American Sniper' which was made into a movie . Wayne Kyle attended the trial, but said it was difficult to be in the same room with his son's killer. 'It was horrible. I mean, gut wrenching,' Mr Kyle said. 'It's just one of those deals, you just wanna jump over that railing and kill him with your bare hands.' Dealing with his son's death has been all the more painful for Mr Kyle, who had a bad feeling about his work helping other vets after he retired from the military in 2009. 'I told him one time, I said "I worry more about you as a civilian that when you were with the teams,' Mr Kyle said. He explained that his son was fully trained and highly skilled when he worked in the military, but 'there's no training to be a civilian'. Childhood: Wayne Kyle was the first to teach his son how to shoot a gun, and gifted him his first weapon at the age of 8. Above, some family pictures of young Chris Kyle . Visit NBCNews.com for breaking news, world news, and news about the economy . Mr Kyle also spoke about a Texas legislator's push to award Kyle with the medal of honor, posthumously. 'If you knew Chris you would know that he would never ever want that. He never saw himself as a hero,' Mr Kyle said. He added that he didn't like Routh's trial being called the 'American Sniper trial' in the media since it distracted from Chad Littlefield's equally tragic death. Chris Kyle served as a Navy Seal  for ten years, during which he became the most lethal sniper in U.S. military history with at least 160 kills. His father Wayne was the first to teach him how to shoot a gun, buying him his first firearm at the age of 8. A film about his life, starring Bradley Cooper, titled American Sniper, was released this past January. In part of the interview, aired on the Today show on Friday, Wayne Kyle described the blockbuster as an 'absolute disgrace' for the way in which it had portrayed his other son, Jeff, who also served in Iraq. Wayne Kyle described the movie, American Sniper, as an absolute disgrace for the way in which it portrayed his other son, Iraq veteran Jeff Kyle (pictured), as 'cowardly' Mr Kyle said that the movie portrayed Jeff 'as a weak, almost cowardly Marine just wanting to get out of the country in anyway possible and that couldn't be further from the truth in the way Jeff is'. However the Today show later said that although Mr Kyle was disappointed with the movie, he did say he was grateful for the attention it brought to veterans. The father also spoke about how he copes with criticism leveled at his son's record as the American military's most deadly sniper. 'I basically ignore it, I know it's not true,' Wayne Kyle said. 'To me, those people have no self-worth... their only claim to fame is to try to destroy somebody who has the values like what Chris possessed.' His father choked back tears as he recalled the thousands of people who lined the route on the day of Chris's funeral. He said: 'If anybody ever wondered if Texas stood behind and supported their veterans, they just had to see that.' On the big screen: American Sniper, the movie based on Kyle's memoir starred Bradley Cooper (pictured), was released in January .
Wayne Kyle is the father of Navy SEAL Chris Kyle - the most lethal sniper in U.S. military history . Kyle was shot dead in 2013 four years after retiring while he was trying to help a fellow veteran struggling with PTSD . His killer, Eddie Routh, was found guilty of his murder in February and sentenced to life in prison without the possibility of parole . His father said the family now has closure following the end of the trial . A movie about Chris Kyle's life called American Sniper was released in January starring Bradley Cooper . Wayne Kyle called the movie an 'absolute disgrace' for the way in which it portrayed his other son, Iraq veteran Jeff Kyle, as 'cowardly'