There is limited research targeting communication interventions for children with severe/profound intellectual and multiple disabilities. This study addressed outcomes from a communication course for parents of children with severe/profound intellectual and multiple disabilities and follows up on a previous publication by Rensfeldt Flink et al. (2020). Potential observable changes in the children's and parents' communicative behavior were studied as well as the parents' experiences of the intervention process and the effect of the course on parent--child communication. A mixed-methods design with a case-study framework was used. Two mother--child dyads participated. Data were collected before, during, and after the course. Video-recorded repeated play interactions by the dyads were coded and analyzed for the mothers' responsivity and use of augmentative and alternative communication and the children's interactive engagement. Longitudinal interview data from the mothers were analyzed thematically. No clear signs of behavioral change were observed in the coded video data. However, thematic analyses showed that the mothers experienced changes to communicative behaviors. Moreover, the course affected both mothers' reasoning about communication with their child and their child's communicative needs. The mothers' narratives contributed insights into how reflective processes might guide action in parent-mediated communication interventions. The implications for research and clinical practice are discussed.