Apologizing after victim blaming

It's not an excuse but here's a brief explanation/backstory. My household growing up was a very "If u wear that it's your fault" type of place. Although I disagreed i didn't realize how much of that I was internalizing as time went on...

TW: mention of SA

A few years ago one of my close guy friends was SA'd at our summer camp. This isn't my story to tell so I won't get into details or anything. He confided in me about it afterwards, I think I was the first person he told. While he told me he was laughing and seemed anxious. I was confused and thought he wasn't taking it seriously. I remember being so infuriated with the girl who did it to him and the fact that it happened to him period.

Ignorantly, I took it upon myself to decide how to handle what happened to him despite his hesitations. I reported it but the camp authority failed to do anything about it. I was so impulsive about the whole thing, didn't even think before what I said and did. But I didn't think it mattered since I was doing "the right thing".

I won't even repeat the things I said to him because it was just so awful. So much really intense victim blaming. Subconsciously i was attempting to manipulate him into taking action since it was clear at that point I couldn't do anything about it on my own. I didn't stop berating him about it until at he ended up saying that he didn't want me to bring it up anymore and that he didn't want to talk about. He was clearly not joking when he said it. I don't think I'd ever heard that particular tone in his voice, it was serious and I could tell he was in pain. We never spoke about after that.

Fast forward, we stayed friends but drifted apart after while. I stopped thinking about it all together pretty much. Went to to college and took a class about childhood trauma. One day the professor asked if we had friends or family that had ever told us about their SA and my brain instantly made the connections...the more I learn the more I understand how fucked up that was.

As far as I know, no one in his life supported him in the way he wanted/needed. He deserved and deserves so much better and I know I let him down and that there's no undoing it. I want to hold myself accountable and apologize but I'm worried cuz I don't wanna trigger him. Idk how he's been handling his trauma or if he's spoken about it in a while so I don't know how to approach the subject.

I just wanna tell him that I know now. I get it. [I definitely wouldn't mention it but ive been SA'd a few times since then so i really get it] I can't undo my mistakes but I can own up to them. I don't expect him to forgive me or not, but he deserves to hear it if he's willing to/wants to.

Any words of advice?