COLUMBIA, Mo. (KMIZ) Charges have been dropped against a Mexico, Missouri, man accused of shooting and killing his brother more than two years ago. Charges of second-degree murder, armed criminal action and unlawful use of a weapon against Stephen Welch were dropped last week, said Audrain County Prosecuting Attorney Jacob Shellabarger. Boone County Prosecuting Attorney Roger Johnson had been overseeing the case as a special prosecutor. Johnson …