People with dementia often experience social isolation in daily life. Generative AI (GenAI) technologies, producing seemingly new content on the spot and tailoring it to users’ wishes, open new avenues for promoting meaningful social connections in dementia care. This study involved 17 people with dementia in 6 workshops and explored how they responded to and perceived three GenAI models, Copilot, Midjourney, and Suno, with a focus on social connectedness. Our results reveal that people with dementia engage in a relational process when using GenAI together: they collectively evaluate the outcomes of the models and negotiate further prompts. Moreover, they gradually develop an understanding of GenAI and become more critical about its output. We contribute to HCI by demonstrating how GenAI can foster social bonding between people with dementia through the co-creation of shared realities, and by discussing guidelines for designing effective and ethically responsible GenAI for people with dementia.