Mr. Cassidy, retired government worker for over thirty years at Aberdeen Proving Ground, Maryland, died on October 21, 2026. He was 81 years old.

After retiring from the government, he worked as a Systems Analyst for Quantum Research International for six years until his retirement from there.

He loved traveling to Nantucket, Martha's Vineyard, Ocean City, and especially to Duck, North Carolina on the Outer Banks with his wife, Sheila, and their best friends, Peyton and Dale Niswonger.

He is survived by his wife of 59 years, Sheila. Their 60th anniversary is October 29th. He is also survived by his son, Mark Cassidy and his wife Kim of Bel Air, Maryland and his granddaughters Nicole Cassidy Meushaw and her husband Tyler, and Marlaina Cassidy. Mr. Cassidy was predeceased by his daughter, Deborah Cassidy and his parents Irene and Thomas Cassidy.