That's great detective work about the trigger (talking to your mom) and the dissonance with office furniture for whomever it was that came forward.

So now you can test to see if interactions with your mom (or interactions about the topic you were talking about) brings someone forward who is otherwise not very active, or is not usually out while you're in your therapist's office. (in this case, sounds like a year since they were out in your therapist's office?).

A lot of what I/we do is about locating those triggers and working back from there. In my case, it's because some who get triggered are causing a lot of problems for me in daily life, so figuring out who has moved forward, and why, gives our therapist and me something to work with. So, that's how it works for me. With you, it may be different, but it does sound like a triggering thing happened with the conversation you had with your mom.