Douglas Lee Horstmann, 69, of Cassopolis, died peacefully Friday, October 17, 2025.
His life began April 8, 1956 in South Bend, Indiana the son Roy and Sally Horstmann.
He married Susan Mock on September 19, 1981 in South Bend. She survives.
Doug grew up in Monroeville, Pennsylvania, where he graduated from Gateway High School. He went on to earn his Bachelor of Science degree in electrical engineering from Ohio Institute of Technology. During that time, he spent his summers on Diamond Island with his grandparents. He met his future wife Sue, while operating the island barge. Doug worked for American Electric Power Company for forty-six years, later becoming the Telecom Manager. His department team was his second family. Doug was an avid Notre Dame fan and volunteered as an usher for many years. He enjoyed cheering on the Pittsburgh Pirates, Steelers and Penguins. Doug had a special group of friends that were very cherished and considered family. He loved living and raising his family on Diamond Lake in Cassopolis. Doug was very patriotic and loved his country. He devoted many years to the annual fireworks show and a new barge restoration. Doug was a devoted father and grandpa who cherished every moment he had with them. He supported his children through college and all the activities they were involved in.
Doug will be greatly missed by family and friends. He is survived by his wife of forty-four years, Susan L. Horstmann of Cassopolis; one son, Steven A. (Bryanna) Horstmann of Osceola; two daughters, Michelle D. Horstmann (Matthew Mishler) of Cassopolis, Stacey L. Horstmann-Roth (Jacob Roth) of Edwardsburg; four grandchildren, Kenley Q. Horstmann, Aubree L. Horstmann, Sharlotte L. Roth, Nicholas G. Mishler, his two loving puppies, Dublynn and Flynn. He was preceded in death by his parents, sister, Laura Nedderman, mother- in- law, Beverly Mock and his father-in- law, F. Eugene Mock.
The family will observe a private remembrance. The Horstmann family prefers contributions, in Doug’s name, to go to the family for future designation. Check to be written to Susan L. Horstmann.
Arrangements have been entrusted to Wagner Family Funerals Connelly Chapel, Cassopolis. Please share a memory or a message online: wagnercares.com.
Posted On: Tuesday, October 21, 2025 4:02 PM
