BOSTON — An 80-year-old man who ran a multistate marijuana-dealing operation faces sentencing in a plea agreement that calls for up to seven years in prison.Marshall Dion has a sentencing hearing scheduled for Thursday in U.S. District Court. Judge Denise Casper postponed the hearing last month after she questioned prosecutors and Dion's lawyers about why the proposed sentence in the plea agreement is only five to seven years when federal sentencing guidelines call for 30 years.