I've namechanged and will be deliberately vague.
DH's brother was sexually abused by their uncle as a kid. This only came out a few years ago and DH doesn't know the full details. Him and his brother aren't close, and in fact we are NC with him at the mo. He is an arse, and is using his abuse as a reason for his awful behaviour over the past 20 years. This may well have jaded him but even PIL are skeptical about the abuse claims and aren't 100% sure it's even all true.
DH told me last night that he can remember 2 incidents with his brother that he "can't decide if it was normal brotherly curiosity or something more sinister". He can't remember how old he was, possibly 8 or 9 (his brother is 3 years older). He's not upset about it as such, but he's confused and angry.
When his brother told of his abuse, DH said that things fell into place a bit more with regard to these 'incidents'. As I say, he doesn't know the detail of his brother's abuse but is angry over the possibility that his brother may have repeated the uncle's alleged actions on DH.
DH feels really burdened by this "secret" now. He doesn't want to talk to his parents about it as he thinks they have enough to deal with various other crap the brother has caused over the past few years. He is full of hate for his brother over this crap from the recent years (and, I suspect, because of what his brother did to him) so wouldn't talk to him about it. He also doesn't know if a) he wants to piece it together and b) what good it would do to remember/know/understand more anyway.
I'm distraught that my lovely DH has been a victim in all of this too and I suspect the impact of it all is going to hit DH slowly over the coming weeks/months/years. I'm seething with his brother but there is also a part of me that feels desperately sorry for the confused and abused soul that he is and that if those things were being done to him as a kid, it's conceivable that he could also do the same - with or without understanding it was wrong.
Obviously I've said to DH that I'm here to talk only if/when he wants (he can be a pretty closed book sometimes - which kind of makes sense now). He's sad at the mess of the situation and had, until recently, remained loyal to his brother despite disagreeing with his actions and behaviours "he's my brother after all" but I think that's changed now.
What the hell does he/we/I do from here?
I don't want this to eat away at him and don't think he should shoulder the responsibility of protecting his parents, or brother, from this but can totally see that he can't really go anywhere with it.