Lexington – Mr. John Dennis O'Brien, of Lexington, died Saturday, February 7, 2009 at his home. He was 56. John was born in Newton on September 17, 1952, a son of the late George L. and Eliza M. (Thibodeau) O'Brien, and had been a Lexington resident for the past several years. He was the brother of the late Kevin O'Brien. John leaves his sister, Nancy M. O'Brien-Duke of Kingsburg, California; his aunt, Elizabeth Donovan of Waltham; many cousins living in the area and his fellow residents and the staff of the Edinburg Center of Lexington with whom he made his home. Family and friends will honor and remember John's life by gathering at 12:30 p.m. on Tuesday, February 10th in The Joyce Funeral Home, 245 Main Street (Rte. 20), Waltham where his funeral service will be held at 1 p.m. Burial will follow in Calvary Cemetery, Waltham. Memorial donations may be made to the Edinburg Center, 1040 Waltham Street, Lexington, MA 02421 or online at www.edinburgcenter.org