His sister, Julie Wilner, posted the following update to Facebook: "He is still very critical, and the next few days will be important as the doctors assess his condition."
Constable Johnston suffered that brain injury while directing traffic late yesterday on Highway 146. A driver went around a line of traffic and through a barricade, hitting a patrol car that had its lights on and careening into the constable.
The DPS said the case is still under investigation and no charges have been filed against the driver. The department is waiting on blood test results and also examining the black box from the driver's vehicle to determine exactly what was happening at the moment of the crash.
Meantime, the Liberty County Sheriff's Office says it has been flooded with calls for concern about Constable Justin Johnston. A fund has been set up for the family and donations can be made at any Prosperity Bank to the "Justin Johnston Benefit Fund."