According to the developer, Castle Rock/Allen, the facility being constructed next to the Dollar General is going to be an office/facility for the Texas Department of Assistive and Rehabilitative Services (DARS).

According to their Web site,DARS is composed of four divisions focused on people with disabilities and children with developmental delays. The department includes the Division for Rehabilitation Services (DRS), the Division for Blind Services (DBS), the Division for Disability Determination Services (DDS) and the Division for Early Childhood Intervention (ECI). 

Thank you for your research.   A community assistance/resource center is better than a late night business. 

As someone who has a son currently involved with DARS,  Its a good thing to have an office this close.