Celebrity Kimberly Williams-Paisley Shares Revealing Wedding Video That Foreshadowed Mother's Dementia: 'She Was Acting Very Irrationally' In an interview with Today, Kimberly Williams-Paisley shares video of her mother at her wedding By Chancellor Agard Chancellor Agard Chancellor is a staff writer covering TV and occasionally comics. He's still upset that Hugh Laurie never won an Emmy for House. People Editorial Guidelines Published on April 5, 2016 03:50 PM Share Tweet Pin Email Photo: Allison Michael Orenstein Kimberly Williams-Paisley's wedding to country singer Brad Paisley is a pivotal moment for the family because it was one of the first times they realized her mother's health was deteriorating. In an interview with the Today show, Williams-Paisley shared a video of her mother, Linda Williams, struggling to read a passage at the 2003 wedding ceremony and said they noticed something was wrong because she was "acting very irrationally" and was "very emotional." "[She] really wanted to be involved in the ceremony at the last minute," the Father of the Bride actress told Today. "So, we gave her something to read, and she stood up in front of the congregation and wasn't able to get through the reading, which was very atypical of my mom." In 2005, Williams was diagnosed with a rare and incurable form of early-onset dementia called primary progressive aphasia. Williams-Paisley – who details her family's journey coping with her mother's dementia in her new book Where the Light Gets In: Losing My Mother Only to Find Her Again–says she first noticed changes in Williams' behavior in 2002 when she told her mom she was getting married and was met with silence. "We are such a close family and I was the first kid to get engaged, and I thought, 'That's what it is,' " Williams-Paisley told PEOPLE. Before the diagnosis in 2005, Williams-Paisley, her father, journalist Gurney Williams, her sister, How I Met Your Mother actress Ashley Williams, and her brother, Jay Williams, also noticed that Linda started having trouble pronouncing words and signing her name. Throughout this struggle, Williams-Paisley says her husband has been an important source of support. "He's been amazing," she told PEOPLE of Brad. "More than anything, he keeps me laughing. That's the best. He's got this dry sense of humor." With this new book, Williams-Paisley and her family hope they'll be able to also help other families dealing with the illness. Gurney, who was Linda's primary caregiver until she moved to a long-term care facility in 2012, shared lessons he's learned in an essay for PEOPLE. "Enjoy each other while you can. Travel. Slow down. Savor your time together," he wrote. Where the Light Gets In: Losing My Mother Only to Find Her Again is available in stores now.