The COVID-19 pandemic has presented unprecedented challenges for people, including young children. This study focuses on how teachers and parents foster children's prosocial behaviours during online learning amidst the pandemic. Data were sourced from 100 articles on WeChat Official Service/Subscription Accounts (WOSA) -- a popular Chinese social media platform -- and from semi-structured interviews with three teachers and six parents, analyzed using content and reflexive thematic analysis methods, respectively. The key findings reveal that children demonstrated increased pandemic-related prosocial behaviours, as a result of specific strategies implemented by both parents and teachers within their sociocultural environment. These findings emphasize the importance of digital platforms and the collaborative practices of teachers and parents in supporting children's social development during a social crisis, offering insights for shaping educational policies and practices. Future research could explore the long-term impact of pandemic-relevant practices by teachers and parents on children's well-being across diverse cultural contexts.