LOS ANGELES - The family of an American man missing along with his wife since the suicide bombings in Brussels that killed at least 31 people has learned that he died in the attacks, his brother said on Saturday.Justin and Stephanie Shults, originally from Tennessee and Kentucky and who were living in Belgium, were last seen dropping off her mother at the Brussels airport shortly before the check-in area was rocked by the powerful explosion on Tuesday."We found out today that cowards took my brother's life just weeks after his 30th birthday," Levi Sutton said in a post on Twitter."He was smart and kind and generous. I never met a single person who didn't like him. He worked hard his whole life and achieved goals that most could only dream about," Sutton said in the post.Stephanie Shults remains missing. Sutton tweeted earlier on Saturday that her car had been found at the Brussels airport.A US State Department official declined to comment out of respect for the families.