This paper examines how structural language analysis is fruitful in uncovering mental states. The psychological theory of Mentalization, which works to uncover how people work to understand others’ and their own feelings, thoughts, desires, and intentions, has used a more general approach to language as a means of assessing mentalization. In this article, a recent proposal to modify this approach by adding Functional Grammar as an aspect in the assessment will be used to analyse and assess the mentalization skills of an informant. A further goal of conducting this analysis is to assess the informant’s mentalization skills with regards to his autism diagnosis, which in the early stages of the theory of mentalization would have ruled out the presence of any mentalization skills. The paper concludes that the informant is well able to mentalize and that this comes to show by way of the linguistically informed method to assess mentalization.