One of the colleagues I manage is very childish and often says that everything is too difficult and her workload is unfair. I try my best to support her but I feel like an unpaid therapist most of the time. She often tells me her mental health is bad and she can't sleep so I referred her to HR and we developed strategies to help her. However, if I tell her something she doesn't like she tells other colleagues and ignores me on the bus and is generally sulky. Today on the bus she was talking loud and proud about how she is going to quit and find a new job etc. I was just sitting there so it was awkward. I have a meeting coming up with my boss who I feel should know about this but part of me feels like a snitch. However, her behaviour is starting to impact my ability to focus on work. Would it be a snitch move to tell my boss she is openly talking about leaving?