With the accelerating growth of the aging population and changes in family structures, the demand for supportive living environments and social interaction among older adults has grown significantly. However, traditional qualitative methods often fail to fully capture the nuanced needs of older adults due to communication barriers, memory limitations, and psychological stress. This study proposes an innovative research approach using an AI-driven age-inclusive digital agent in Mixed Reality (MR) to explore long-term interactions with older adults ageing in place. By creating intelligent digital agents designed after individuals, pets, or objects familiar to older adults, these agents aim to unobtrusively investigate how the residential environment influences daily routines among older people. Insights gained through natural interactions in MR can inform the design of residential spaces, better satisfying the needs of aging populations. This proposed approach aims to improve both home redevelopments and future residential designs for older adults.