O'BRIEN, John J. Suddenly, of Winthrop formerly of Brookline on April 6, 2016. Loving father of Paul W. O'Brien of Lynnfield. Companion of Nancy Waldron of Winthrop. Son of the late William E. and Mary K. (McCabe) O'Brien. Dear brother of Bill O'Brien and wife Margie of Omaha, NE., Bob O'Brien and wife Mary of Walpole, and Jean Beattie and husband Brian of Winthrop. Also survived by several nieces and nephews. Visitation will be held on Saturday April 16th from 9:30 10:30 in the Bell-O'Dea Funeral Home, 376 Washington St., BROOKLINE followed by a Funeral Mass in St. Mary of the Assumption Church, Brookline at 11:00. Interment to be private. In lieu of flowers donations may be made to Dana-Farber Cancer Institute, P.O. Box 849168, Boston, MA. 02284-9168 or www.dfci.org