Mark Alvin Sandau passed away at his home in Punta Gorda, Florida, on April 16, 2026, at the age of 75. During his final days, many loving family members were by his side. Mark courageously battled Parkinson's disease for 22 years, along with heart disease and cancer, yet he never lost his determination to take life one day at a time.

He was the proud son of Alvin Edward Sandau and Delora Jewel (Flack) Sandau.

Mark is survived by his wife, Jacqueline Irene (Bomar) Sandau, with whom he shared 52 years of marriage. The two met while serving in the Air National Guard and were married on January 12, 1974. In January 2023, they retired together to Punta Gorda, Florida. He was a devoted father to his daughters, Meg (Brian) Carlson and Anne (Aaron) Tuck, who will miss him deeply. As a grandfather, Mark found immense joy in his family. He was especially proud of his grandson, Dylan Carlson, a recent graduate of Missouri University of Science and Technology with a degree in Civil Engineering. His granddaughter, Haylee Carlson, is graduating from Liberty High School and will attend the University of Nebraska-Lincoln as a member of the Scarlets Dance Team. His granddaughter, Rylee Carlson, will graduate from Liberty High School next year and is a member of the Liberty Belles Dance Team. He also leaves behind two step-grandsons, Carson and Braden Tuck.

Mark also cherished time spent with his nephews Joel, Jesse, and Jordan Hermann; his niece Amber Meyers; and his nephew Ryan Meyers. He created many special memories with his brothers- and sisters-in-law, grandparents, aunts, uncles, cousins, great-nieces, and great-nephews.

Known for his sense of humor and loyalty, Mark maintained many lifelong friendships and shared countless memorable adventures with those he loved, from golfing outings to attending sporting events of all kinds.

Mark loved his career and took great pride in his work. From Bomar Real Estate to serving as President of Mortgage Banking at Heartland Bank, he dedicated himself to his profession and community. He also served on numerous committees and organizations, including as President of the Northside Realty and Mortgage Banking Association.

He was preceded in death by his beloved sister, Julie Ann Sandau Hermann, and his dear brother, David Alan Sandau.

A Celebration of Life will be held at Forest Hills Country Club, 36 Forest Club Drive, Chesterfield, Missouri, on Wednesday, June 3, 2026, from 1:00 p.m. to 4:00 p.m. Visitation will be held from 1:00 p.m. to 2:00 p.m., followed by a sharing of memories from 2:00 p.m. to 3:00 p.m.