Am I being irrational?

So today I found out that by my MIL that her son (my partners brother, my son's uncle) got molested as a child, she swore up and down that he would never do anything to my son, but now I'm paranoid and anxious. He is in his 30's now, got molested when he was 6 years old by his 10 yo cousin and didn't tell anyone until he was in his 20's.

I don't want to leave my son around him alone (or anyone that isn't me, his dad or his grandparents) one thing that really got me is that my MIL said that he doesn't want to have kids of his own? Which I found super odd because watching him play with my son with blocks and stuff, he's very good with kids and likes being around them as I see and he's almost childlike himself the more I watch him... So why wouldn't he want kids of his own? I just find it strange... And it makes me even more paranoid.

I'm going to get my haircut tomorrow and I'm leaving my my son with my MIL and I'm hoping that his uncle goes to work and STAYS at work while I'm gone... I didn't know this about him until today, but he's staying up here with us for a couple of days because my partner has gone down south for work so they called my son's uncle to come up to work here at the farm because my partner couldn't. But why would my MIL tell me this WHILE he's here and around my son? (PS my son is 10 months old and this is the first time he's met his uncle, haven't seen him since I 6-7 months was pregnant).

Like did she feel the need to tell me because she herself feel down doesn't trust him either? I'm just so paranoid.

But anyway I'm so scared to go get my haircut and leave my son here if his uncle is here... This sucks.. am I being irrational? 😔