The experience of family members of children with autism spectrum disorder (ASD) is not uniform. This study focused on mothers of a child with ASD (Study 1) and typically developing siblings (TDSs) during their emerging adulthood (Study 2). Similarities and differences were explored regarding a proposed model examining the paths of perceived social support (PSS) and normalization (a coping strategy) with subjective well-being: satisfaction with life (SWL) and positive affect (PA). Similarities were found in the paths between PSS, normalization, and SWL, in mothers and TDSs, but differences emerged regarding PA. These findings highlight the importance of PSS as a resource that contributes to normalization and SWL. Professional awareness of family members' PSS and their engagement in normalization is needed.