My (23F) boss (30M) left his suicide note for me. He lived and now I don’t know what to do. What do I say?

I work in the chemical and equipment room for my university’s undergrad organic chemistry labs and have been working for my new boss for about six weeks now. I only have a handful of other coworkers and my boss, so we’re a pretty close workplace but our relationships are mainly professional. I don’t know my boss very well at all. We talk for maybe a few minutes every shift I work and it is always small talk.

Yesterday morning I got to work early and the door to our room was locked. I was waiting for my boss to show up and unlock the office when I noticed a letter slid between the desk and roll down door. It was addressed to “Reader” and was signed by my boss. After I realized what it was, I ran downstairs to the chemistry department office and gave it to the first person I saw who called him immediately to check on him.

He picked up instantly and said he was pulling into the parking lot as we spoke. As far as I know, the department staff has made sure he is getting the help he needs and he will be back at work when he’s ready. I was sent home since I was absolutely beside myself and have been doing very badly since.

I have lots of questions and am having a hard time working through my feelings. I am not close with my boss and we have never had more than surface-level conversations. He had to know that I would be the one to find the note because I was scheduled for first thing in the morning. I was the last person to leave the night before and there was no note, so it wasn’t possible for anyone else to find it. He and I are the most close of him and any of my other coworkers so his choice to leave it while I was scheduled isn’t completely surprising, but still odd considering how little we know each other. I know he is a very socially awkward person and I would guess that he doesn’t have much social life outside of our job, but I just keep thinking that surely there was someone else closer to him that he could’ve left a note for.

I know I will have to see my boss again. I don’t know if he’s going to want to talk about it and I don’t know if I’m comfortable being around him anymore. This was all just so strange and completely thrust on me without any warning. What should I do and say when I see him again? Should I talk about what happened or just keep things entirely professional? Any advice will be much appreciated.