▶ Watch Video: Harry Dunn’s parents on U.S. civil lawsuit Almost three years after 19-year-old Harry Dunn was fatally struck by a vehicle, his parents are in the United States fighting for justice. The British teen’s father wants answers from Anne Sacoolas in particular, the American woman involved in his death. “I just want her to own it — her accountability — for what she has done to us as a family and to my son. And I need to ask her why she left, why did she think it was okay to leave my son there and — and just leave the country. It still hurts after two years not knowing,” Tim Dunn said in an exclusive interview on “CBS This Morning” Friday. “I feel like my son’s life was just — I don’t want to be horrible, but like it was — meant nothing to her,” he said. Harry was killed in a collision with Sacoolas outside a British military base in August of 2019. The teen had been riding a motorcycle. The mother of three admits to driving on the wrong side of the road. Sacoolas fled the U.K. just days after the crash, claiming diplomatic immunity as the wife of a U.S. intelligence official. The teen’s parents, Tim Dunn and Charlotte Charles, gave in-person depositions Tuesday at a Virginia court as part of a civil case they brought against Sacoolas for damages. “Of course, it was grueling,” said Charles, who admitted she had no idea what a deposition was until “a few weeks ago.” “It’s really hard. You’re trying to get across to them how loved he was, how much we loved him, how much he’s missed,” she said. U.K. parents give evidence in crash case 02:13 Harry’s parents say their grief is getting “worse every day.” “The pain and the suffering is getting worse if anything. The continued fight, exhausting,” Charles said. Tim Dunn said the struggle even strained his home life. “My wife Tracy has to put up with me — I’m argumentative, I’m sad all the time, I struggle to get motivated,” he said. “I’m really, really struggling at the minute.” Dunn and Charles’ quest for justice has even reached the ear of world leaders. Former President Trump invited them for a meeting at the White House in 2019, which the parents later likened to a “stunt.” He had offered then for them to meet with Sacoolas, who had been waiting in the next room, but they declined and said they were not emotionally ready. “We didn’t realize we were going to see President Trump. You know we got told it was a senior official,” Charles recalled. The topic of Harry’s death surfaced again in a meeting between Prime Minister Boris Johnson and President Joe Biden ahead of the G-7 summit. Dunn and Charles said they were “pleased” Harry was brought up, though they have yet to hear directly from either administration. “We found out from the media. So we were heartened to hear it, but a little bit disappointed that we found out the way we did. But nonetheless, it’s a positive step forward,” Charles said. Dunn added that they were still “absolutely” willing to meet with Johnson. As for Sacoolas’ punishment, Charles simply wants her to hold herself accountable and face the British justice system. “We’ve known for a long, long time now that she’s able to return to the U.K. of her own volition to face U.K. justice. “What happens after that, we have no control over that. But we’re just asking her to get to the starting point.” A representative for Anne Sacoolas told CBS News they have no update at this time.