Would you tell your husband's family the truth?

My husband is a very sweet guy and I love him more than anything. He had a son when we met and I have adopted him as helped raise him as my own and then we recently had a baby together. My husband never gets to see his family because they live far away. We went to see them for Christmas and my husband had us leave early because his mom's sister and her husband came. He was acting weird about it and he told me that night that it's not a big deal and he's fine but his uncle got him his very first drink when my he was 16 and he woke up to his uncle assaulting him. But he said his uncle apologized and they never talked about it again nor did it happen again. His uncle is almost 60 now which means he was in his 40's when this happened. I feel like my husband should tell his family because his uncle is around kids. My husband makes excuses saying his uncle was drunk and that it was partly his fault because he was always making sex jokes and stuff back then so maybe he accidentally tempted him. I told my husband 16 year old make sex jokes all the time. My husband never told the rest of his family because he thinks it was just a drunken mistake his uncle made that he was at fault too which he wasn't. I don't want to break my husband's trust but that uncle is around other kids. Would you warn your husband's family?