Is it unprofessional to talk about your stillbirth at work when someone tells you that the reason they (coworker) yelled at you is because they're having a hard time?

I have a male coworker who is very volatile and known for his temper. Realistically he should be fired. It's abusive and I can't stand working with him.

Today I went to him and asked him to sign papers he submitted. He said he doesn't have time. I told him that it doesn't have to be right this second, but I need them by 3pm because I have to send off the statements today.

He instantly started raising his voice and said "Yeah I'll get right on that, thank you. Not like I have ten million other things to do today but whatever. You can't just let it slide noooo..." Then he started getting louder and threw his phone down on the desk. "You have to come in here with your PERKY little attitude smiling as you pile on more shit." Then he yelled "Thank you. Thank yoooou!" And slammed the door as he left.

No one else other than reception heard this. I went to our boss and explained what happened and he said "Yeah well we all know he's got a temper and we need to tread carefully."

I said no, this is abuse. I made a reasonable and polite request that realistically, he should have done before he submitted the paperwork anyway. My boss started defending him and talking to me about what I could have done to "mitigate the situation" because apparently my coworker has a lot of personal stuff going on (none of which has ever been communicated to me because it's no ones business). My boss said so I "should think about that because maybe he's not having the best day and he needs some forgiveness". I told him, respectfully, his answer is not acceptable and I am stepping away.

I went straight to HR and said that this abuse is not warranted (no abuse is) but especially today.

EDIT FOR CLARIFICATION: HR asked what happened today, so I told her that four years ago, I had a stillbirth on April 4th. My baby died suddenly due to a true knot in his cord. I had no idea and went to the ER because he wasn't moving. Unless you've been through it, you have no clue about the trauma.

The lady in HR was very uncomfortable while I was telling her about my stillbirth. I spoke about for maybe 20 seconds. I was hired after it happened and have since had a baby so no one knows about my stillbirth.

Do you think, given everything else, that it's unprofessional to talk about that at work?

Further edit for clarity: I wasn't intending to tell them about my stillbirth but she asked what happened 4 years ago and yes, I did say "especially not today" which led into that convo.