Mark C. Cassidy

Dateline: Bethalto, Illinois
Mark C. Cassidy, 69, of Bethalto, passed away on Saturday, November 8, 2025 at his residence. He was able to fulfill his wishes to stay at home due to the wonderful care and love provided by his care team led by Amy, and the care of BJC Hospice.
Mark was born in St. Louis, MO, on July 24, 1956, the son of Claude R. and Fern E. (Doolin) Cassidy. Mark was proud of being a United States Navy Veteran who served on a minesweeper. He was a member of the First United Methodist Church in East Alton, and before he was diagnosed with ALS, he was active with helping with the sound equipment and other needs at the church.
Mark loved living life to the fullest and having fun! He was always up for a challenge, even with ALS he went paragliding, took a flight in a hot air balloon, and a sail plane ride! He had many hobbies, some of which were computers, taking care of birds (especially hummingbirds), trying to predict an accurate weather forecast, and watching the beauty of the trees. He loved animals, especially his last dog Zoey. She was a perfect dog for him during his illness. Mark loved to talk and had a boisterous voice that is missed. He was a jokester and loved to laugh and bring laughter to others. Mark was a very good cook and could tell if a dish needed a little more of a certain spice, especially Cayenne Pepper!! He had a huge, kind heart and was generous, always ready to help those in need and give what he could.
Survivors include his son, Ryan, of Australia; brother, Michael (Marilyn) Cassidy of Glen Carbon; a niece, Laura (Sam) Brasses; a nephew, Bryan Cassidy; and two great nephews, Jonah Cassidy and Luke Brasses.
Along with his parents, he was preceded in death by a sister, Melissa Ruth Cassidy.
Visitation will be held on Wednesday, November 19, 2025, from 4 pm until a service at 6 pm, at Elias, Kallal and Schaaf Funeral Home in Bethalto. Pastor Ed Granadosin will officiate.
A private burial will take place at Jefferson Barracks National Cemetery in St. Louis.
Memorials are suggested to the ALS Association.
Online condolences and guestbook may be found at www.eliaskallalandschaaf.com