The purpose of this study is to describe and discuss the development of a high-fidelity prototype that aims to support people with dementia (PwD) in dealing and mitigating non-cognitive symptoms associated with their disease, like anxiety, depression or pain. The prototype comprises interactive mockups to enable a co-creation session and subsequent usability testing with healthcare professionals of PwD. Its innovative contribution lies in combining multiple evidence-based interventions (reminiscence therapy, music therapy, journaling, VR mindfulness) with an AI-powered conversational agent within a unified, co-designed interface specifically adapted for dementia care. The prototype was designed with input from existing evidence and guidelines on dementia as well as from expertise from healthcare professionals treating PwD during a first co-creation workshop with those professionals where valuable feedback will be integrated for the next iteration. Key findings include specific design requirements for AI safety in dementia care, privacy protection strategies, and a validated methodology for iterative co-design that bridges professional expertise with end-user needs. Researchers can now adapt for specific needs and challenges that can come up in the next co-creation sessions, with materials and contents that were thoroughly revised and tested, potentially more adequate for successful interactions with PwD. Future steps include a second co-creation session with PwD and informal caregivers to collect perceptions, preferences, needs and concerns regarding the prototype.