If one of your friends hurt another of your friend's feelings, and they seem clueless that they were hurtful, would you tell them they upset the other person?

One of my friends told me he was hurt after overhearing something this other friend said about him. This is at work: “She” who upset him is the boss, and we work for her. He acted quiet all day, and she was busy and distracted, and therefore clueless that she upset him. I don’t think she intended to upset him, and it may be that what she said was not meant to upset him, maybe it came out the wrong way, maybe he took it the wrong way.

If you’re wondering what the subject was, he, through his contacts, got a vendor to donate a computer to a fundraising effort. Someone asked her if they should thank him, and she said “Hell, no.” He was behind her, so she didn’t know he overheard. Other people heard her say it, too. I would like to think she didn’t mean it the way it sounded, but who knows. He is a generous person who does a lot for others, and it’s upsetting to him not to be thanked for his efforts.

Gratitude is free, and some words of thanks to him would have been appreciated.

It’s sad seeing him upset and it’s sad seeing her clueless. Should I inform her that she upset him, so that she can address it if she feels it’s helpful? Or should I leave it alone?