Background: The prevalence of cerebral palsy is estimated to be between 1.5 and 3.8 per 1,000 live births. In Mongolia, the incidence is reported to be 1.89 per 1,000 live births. Physical therapy for children with cerebral palsy improved their motor abilities. The involvement of family members plays a critical role in engaging children in therapeutic activities. Aim: Empowering parents and guardians to ensure regular participation in physical therapy is a priority. Materials and Methods: A total of six children aged 4–9 years (2 males, 4 females) with quadriplegia who received home-based services between October 1, 2023, and October 1, 2024, were selected using a case-controlled clinical trial design. A physical therapist visited once every two weeks for 60-minute sessions. Children’s motor development was assessed using the GMFM-88 criteria, and statistical analysis was conducted using SPSS version 26. Results: Following the physical therapist’s guidance, parents conducted physical therapy exercises with their children an average of 4.5 times per week, with each session lasting approximately 26.6 minutes. Statistically significant improvements in motor function were observed at the 3-month (p = 0.020), 6-month (p = 0.006), and 1-year (p = 0.006) reassessments. Conclusion These findings highlight the importance of parental and guardian involvement in supporting the motor development of children with cerebral palsy.