Very few studies have given attention to parental support for children's play-based conceptual development in a home setting. The key aspect of this paper is to investigate how parental support aids development of children's mathematical and science concepts in collective play in the home context and what happens to the play during parent-child collective engagement. The data has been collected through video, audio and semi-structured interviews from four Indian families and their children (four to five years old and median age 4.5 years). For data analysis, Hedegaard's (2008a) three levels of interpretation--common sense, situated practice and thematic interpretations--were employed. Drawing upon Vygotsky's (2004) concept of imagination and creativity, Fleer's (2010, p. 140) pedagogical model of "collective and individual play" and Kravtsova's (2009, p. 22-23) concept of "subject positioning" are used for thematic analysis. The paper analyses the play experience of a five-year-old boy, Jay (pseudonym used) and his mother's co-construction of play in the home context. The findings of our analysis shows that the mother's interactive approach as an active play partner in Jay's play promoted his learning and development. The paper argues that the parents' active involvement in children's play is not only important to develop the play itself but also important for providing better learning opportunities for children.