Diagnosis codes for issues related to "suspected" dementia.

I am new to private practice and Simple Practice. I just met with a client suffering from paranoid delusions that are connected to a "suspected dementia". The "suspected dementia" came from a neurocognitive testing report done by the clinical psychologist who referred the patient to me for CBT. The paranoid delusions appear exacerbated by traumatic experiences related to the onset of this dementia including a major car accident and abandonment by spouse. Would love someone's experience and insight on how to code this using ICD-10. Avoiding a dementia code as this was only a "suspected" dx and I am not trained to diagnose it. Responses appreciated!