John P. Sibert, age 74, died peacefully, Friday January 25, 2013 at his home in Billerica surrounded by his family. He was the beloved husband of Julia M. (Costabile) Sibert, to whom he was married 54 years. Born in Cambridge, March 14, 1938, he was the son of the late Arthur and Helen (Agnew) Sibert. John served his country with the U.S. Air Force. He had been employed with Ahern Plumbing Company in Cambridge for many years before his retirement. A longtime Billerica resident, John was happiest when in his basement workshop, listening to country music, and making new things. Besides his wife Julia, he is survived by his two daughters, Helen Lynch and her longtime companion Freddie Moscaritolo of Billerica, and Jeanmarie Guarino and her husband David of Billerica, and his son, John Sibert and his wife Amy of Lowell. He is also survived by his 11 loving grandchildren, Tammy, Robert, David, Kevin, Christopher, Sean, Jonathan, Amanda, Logan, Madison, and Mackenzie, and 9 great grandchildren, Brendan, Ryan, Mason, Tyler, David, Sean, Megan, Nathan, and Kaylin. He also leaves his two sisters, Jane Marquardo of Medford and Irene Duprey of Cambridge, and his brother, Arthur "Buddy" Sibert of Maine.