The brother of a Tiverton man is admitting to his role in shipping over 200 pounds of marijuana from Pennsylvania to Rhode Island.  Benjamin Daniels of Utah pleaded guilty in Providence yesterday to a federal charge of conspiracy to possess and distribute more than 50 kilograms of marijuana.  His brother Michael Daniels of Tiverton pleaded guilty in the case last month.  The brothers are each facing up to 20 years in federal prison at their sentencings this fall.