( CNN ) -- `` I love you Luke ! ! '' That 's how Ryan Bresette closed a Facebook post on Saturday , a day after his Kansas family -- fresh off a beachfront vacation -- experienced the unthinkable when a display board crashed down on them inside Alabama 's Birmingham-Shuttlesworth International Airport . The crushing weight of the digital sign killed Luke Bresette and left his mother , Heather , in critical condition at a Birmingham hospital , officials said . `` Words can not describe the pain we feel , '' Ryan Bresette wrote Saturday on Facebook , urging people attending church to wear sports jerseys to services in tribute to his sports-loving son . `` Thank you all for the love and support . Keep praying and praying and praying . '' Posts on what appears to be Anna Bresette 's Twitter page said that her mother , Heather , broke both her ankles and her left pelvis ; her brother Tyler suffered a concussion ; and another brother , Sam , broke his left leg and nose . Justin Cohen , from Children 's of Alabama hospital , told CNN on Saturday night that Tyler and Sam Bresette were in fair condition . `` Seeing all these little kids in the hospital breaks my heart , '' Anna Bressette wrote . What caused the large digital sign -- which showed when and where flights were arriving to and departing -- to collapse around 1:30 p.m. ( 2:30 p.m . ET ) Friday ? On Saturday , authorities still did n't know . `` ( Birmingham Airport Authority ) President and CEO Al Denson and the staff are continuing to work with officials to investigate , '' said Gaynell Hendricks , the chairwoman of the authority 's board . `` This includes discussions with contractors , subcontractors that are responsible for the modernization of the ... airport . '' The incident happened in a new part of the airport , in a public area before security checkpoints . According to CNN affiliate WVTM , the area opened up March 13 and includes a covered parking deck , children 's play area , eating establishments , a new baggage system and other features . Larry Snyder was riding up the escalator when he saw the display board fall , telling CNN affiliate WIAT that one family was especially affected . `` The family was crushed , little kids crushed underneath the sign . And everybody was scattering to lift it up , '' Snyder said , adding that he was among those who helped . Video footage showed people sweeping up the area and a cut-out spot along a wall with protruding wires , where the sign once stood . Whatever the reason , it was clear the Overland Park , Kansas , family was in the wrong place at the wrong time . Birmingham Mayor William Bell said he 'd met with Luke 's father , describing him as a `` heartbroken '' man who `` wants and deserves answers . '' `` I can not come close to understanding his heartache , '' the mayor said in a statement . `` But I will get answers . '' Luke Bresette was a fifth grader at St. Thomas More , a Catholic school in Kansas City , Missouri , according to CNN affiliate KCTV . Father Don Farnan , a priest of the affiliated parish , described him as a `` normal kid '' who 'd been on the city champion basketball team and was always at Mass on Sunday mornings . `` He lived a good moral life , '' Farnan told the Kansas City station . `` He was shaped with the behaviors and the attitudes and the strength of what helps make society a good one . '' In the days prior , Ryan Bresette had put up several messages and photos on Facebook about the family 's vacation in Destin , Florida -- including several showing two of his sons playing in the Gulf water , with no one else in sight . His post Saturday , by contrast , reflected his grief and affection for his late son . `` I miss and love Luke so very much . '' CNN 's Janet DiGiacomo contributed to this report .
NEW : Two brothers of the boy killed are in fair condition at an Alabama hospital . NEW : The late boy 's parish priest calls him `` a normal kid '' who `` lived a good moral life '' A flight display board falls on a family at the airport in Birmingham , Alabama . Birmingham 's mayor promises , `` I will get answers '' as to why this happened .