Diane Irene Johnston-McCoy

Diane Irene O’Leary Johnston-McCoy, 81, of Rock Island, Illinois, passed away on Sunday, April 19th, 2026. The Visitation will be held on Thursday, April 23rd, 2026, from 9:00 a.m. to 11:00 a.m. at Halligan-McCabe-DeVries Funeral Home, Davenport, IA. The celebration of life will follow at 11:00 am at the funeral home with Pastor Kenneth Maxwell officiating. Memorial donations may be made to any of the Humane Societies of the Quad Cities.

Diane was born on May 9th, 1944, in Davenport, a daughter of Kenneth and Mary (Johnson) O’Leary. Diane attended Assumption High School. She was united in marriage to Gerald Ketelaar from 1966 to 1978. She worked as a Director’s Assistant in the College Computing Department at Palmer College of Chiropractic and enjoyed her work. Diane decided to attend Palmer College, and graduated with a Certified Technician degree in 1996. Later in life, she married Royce Ray McCoy in May 2023.

She was an avid sewer and cross-stitcher. Diane loved her church, reading, and her family. She especially loved her family and being a grandmother and great-grandmother. Her family meant everything to her.

Those left to cherish her memory include her husband, Royce; children, Christine (Daryl) Ketelaar- Melear, Thomas Ketelaar, and Gerald “Chip” (Tracy) Ketelaar; grandchildren Elizabeth, Gretchen (Dillon), Joey, Ellie, Jack, and William; great-grandchild, Sophie; siblings Kathy (Dave) Rasmussen, Margaret “Peggy” (Dennis) Green, Timothy O’Leary, Bridget O’Leary, sisters-in-law Orvetta O’Leary and Jeanette O’Leary, and many nieces and nephews.

She was preceded in death by her parents, and brothers, Michael O’Leary and Daniel O’Leary.