Therapist

The Therapist was visited by Lara in order to appease her uncle. Unknown to her, he was an affiliate of Trinity.

Sessions with Lara Croft
After returning from Yamatai, Lara made several attempts to regain control of the Croft Estate from her uncle, Atlas de Mornay. He refused on the grounds he did believe she was responsible enough to assume control of the estate, and that she wasn't mentally well after her ordeal and told her to seek professional help, though it's far more likely that he was merely using this as an excuse to try and destroy the Croft name after what happened to his sister.

In order to appease her uncle, Lara began to attend Therapy sessions with the therapist after he was recommended to her by Ana. He tried to get through to Lara, though she was largely defiant. His assessment concluded that Lara was in good mental health aside from her survivor's guilt. Unknown to Lara, he was passing their sessions to Trinity, specifically, Ana who used them to try and see if Lara would be willing to join Trinity and finish her father's hunt for the Divine Source.

Trivia

 * The therapist only makes a visual appearance in the Rise of the Tomb Raider announcement Trailer.
 * In issue 18 of the comics, it is revealed that the therapist was recommended to Lara by Ana. It is very likely that he is affiliated with Trinity in some way. In Rise of the Tomb Raider's, Blood Ties DLC it was confirmed that he is a colleague of Lara's Uncle Atlas.
 * It can be assumed he is the same therapist in the "Sessions" documents.