Montgomery County Detectives and Upper Moreland Township Police have charged a mother and her adult son with drug and gun offenses stemming from an arrest made while the mother was finishing a state prison sentence at a Philadelphia halfway house. She was to be considered for parole next March after serving five years for selling drugs.  They arrested 50-year-old Tonya Taylor Sunday on Easton Road, near an apartment building where she once lived, three days after they arrested her 29-year-old son William Taylor of Abington for an alleged drug sale near the Willow Grove Park Mall.  They found a loaded .38-caliber revolver on the floor of the car she was driving and a loaded .25 caliber semi-automatic pistol in her purse.  Montgomery County District Attorney Risa Ferman says there was a lack of oversight in Tonya Taylor’s case, and someone should be held accountable.  Mother and son are both being held at Montgomery County Prison in lieu of high bail.