21-year-old Xander Jaymes Smith was arrested at the scene and charged with intoxication assault causing serious bodily injury. Javiera Mellafe said her life changed around midnight Sunday because a suspected drunken driver rear-ended her mother. Plano DWI CrashWhat we know:The crash happened near State Highway 121 and Independence Parkway in Plano. What they're saying:Mellafe’s 17-year-old daughter said she found out about the crash after receiving an emergency notification from her mother’s phone. That’s where she found her mother’s car totaled.