John S. O'Brien Obituary

It is with deep sorrow that we announce the death of John S. O'Brien of Grayslake, Illinois, who passed away on December 27, 2025, at the age of 88, leaving to mourn family and friends. Leave a sympathy message to the family in the guestbook on this memorial page of John S. O'Brien to show support.

He was predeceased by: his parents, John O'Brien and Joy Adele O'Brien (Wilson); his brothers, Timothy Michael O'Brien and Patrick O'Brien; his stepbrother William "Bill" Ryan; and his sisters-in-law, Mary Ellen O'Brien, Linda O'Brien and Jane O'Brien.

He is survived by: his wife Cathryn O'Brien; his children, Jeanne Lasheff (Jack), Debra "Debbie" Borsic (Michael), Laura McClory (Jack), John O'Brien (Carri) and Kelly Haeflinger (Brian); his grandchildren, Connor Lasheff (Skylar), Tiffany Rail (Chris), Nora Ramsey (Micheal), Rebecca Doering, Kevin McClory (Emily), Ryan McClory (Erin), Katlyn Ivey (Matt) and Erin Pfeiffer (Landon); and his brothers, James O'Brien and Paul O'Brien. He is also survived by his 16 great-grandchildren, and his 1 great-great-grandchild.

In lieu of flowers, memorials may be made to Tunnel to Towers, City of Hope Cancer Treatment Center or Lightways Hospice.