Tamara (40F) and I (37M) have been friends for a few years. Every year on Mothering Day she posts on Instagram a photo of her son who tragically died a few years before we met along with words of grief.

After this year's post I noticed that she has never mentioned how her son died, which I found a bit unusual. On a whim I googled her son's name and far out I was not prepared for what I unearthed.

There were many articles describing that Tamara had actually killed her son in a paranoid psychotic episode. She did not understand what what she had done was wrong so is permitted to live in the community provided she reports to psychiatry appointments, rather than serve a prison sentence.

I do not feel safe being alone with Tamara anymore. She killed her son after deciding to stop her anti psychotic meds and declining rapidly. What's to stop her from going off them again between psychiatry appointments and potentially becoming a danger to me?

I don't think it's at all likely, but it's at least possible and I don't want to take any risks I don't need to.

I don't even really want to be in group spaces with her for a while because I've recently sensed that she has a bit of a crush on me (unrequited) which was already bothering me as I recall she once described having a crush on someone else in a way that sounded borderline delusional that he was reciprocating. She also knows where I live and I live alone.

I don't think any of our mutual friends know. She goes by a different surname now and the only reason I knew her original surname is because her mother is a public figure in my profession. Oneday when Tamara was describing her mother I happened to connect the dots. I remember Tamara seemed so flustered that I'd guessed but I put it down to her being modest about having a well known mother. Now I'm guessing she was actually concerned about the privacy of her history.

Here's where I might be the arsehole. I would really love to share this news with our mutual friend Kay who I am very close with. I'd like someone to debrief this shocking news with as I feel quite destabilized by it. And I want to be able to ask Kay whether Tamara is at an event before choosing whether to attend myself. Kay runs out hobby group so she is the only one who will know.

But on the other hand it's not my story to tell and Tamara obviously doesn't want people to know. I don't want to potentially make things worse for this vulnerable woman, for whom the hobby group is such an anchor. I also don't want to burden Kay with this info that I sort of wish I hadn't ever looked up myself although perhaps she would prefer to know.

So, WIBTA if I told Kay?