Yeah. Made the mistake of mentioning some of the really messed up stuff I saw to my 2nd youngest sibling when they were 12 and claimed that they'd seen everything on the internet.
They refused to get into the bath for 2 months and cloth washed at the sink.....
Those that think they've seen it all and think they're "immune" or used to it make the dangerous mistake of sometimes searching for NSFL content that are sometimes mentionned on those types of questions just to test themselves.
I've seen a lot, way too much for my own good, it is never a good idea to search something like that up.
Truly hope your sibling as well as yourself aren't too scared of what it was you saw. Some of the content seen can sometime leave pretty heavy or permanent marks.
Oh, it definitely made it's mark on my psyche. This was over a decade ago, almost 2 now. Younger sib is pushing 30, and never claimed to have seen the whole internet again. And I'm a moderately adjusted adult.