Parents with visual impairments (PVI) encounter unique challenges in engaging their sighted children in outdoor informal learning, yet little is known about how to address these barriers. We first conducted interviews with 11 mixed-ability families to uncover the perceptual, knowledge, and interactional challenges that limit parental participation. Building on these findings, we explored design opportunities across device form factors, interaction mechanisms, and modes of AI mediation through a design consultation, which led to the development of Bond, a distributed Wizard-of-Oz prototype. Bond combines a lightweight child-worn camera with parent-facing prompts to deliver timely, context-aware support for joint attention and conversation. A field study with 14 families demonstrated increased parental responsiveness, deepened parent–child dialogue, and strengthened parents’ confidence, while fostering children’s curiosity and co-exploration. We introduce Symbiotic Learning as a conceptual lens that reframes AI as a relational mediator bridging perceptual asymmetry, offering design considerations for inclusive, co-constructed learning in mixed-ability families.