The UCDD provides an unstructured, Sibling Activity Program that is staffed by a lead teacher and several teacher assistants. This program provides the siblings of consumers with childcare, assistance with homework, weekly arts and crafts projects, and opportunities to play computer games or watch videos while their brother or sister and parents attend the formal UCDD programs.

While limited in scope, when consumers have brothers or sisters, the Sibling Activity Program allows the entire family to attend the UCDD Program together.