Drawing on grounded theory and the health belief model, this study investigates the factors influencing surrogate health information seeking intention among older adults in the context of generative artificial intelligence (GAI). Grounded theory was employed to identify core elements and construct a theoretical model, which was subsequently validated through a survey-based empirical study. A total of 55 valid interview records transcripts and 291 questionnaire responses were collected. The findings indicate that perceived susceptibility, GAI trust, GAI literacy, and health information literacy significantly and positively influence surrogate health information seeking intention; perceived privacy risk significantly and negatively influences GAI trust; and information quality and perceived service experience indirectly and positively influence surrogate health information seeking intention by enhancing GAI trust. Health information literacy negatively moderates the effect of perceived susceptibility on surrogate health information seeking intention, while other interaction effects did not reach statistical significance.