my boyfriend have been manipulated to believe that these things didnt happen. He really dont think it happen. I'm together with a man who think his father is all good - but your BF is minimising what happened; he doesn't want to find out any bad about his father!
He is minimising what his father did by saying he (bf) was in the room - his F has told him he was in the room when the 'alleged' attacks took place, bf has taken F word for it, therefore the 'attack didn't happen.' Rather than challenge his father's word, on the date/time/place of the attack (which he was convicted for!)
He minimised the attack(s) by saying the child/family only want money.
He is minimising the looking at child images, which the F freely admitted turned him on [boak] by saying it was only a few, and they were clothed
He doesn't want to admit his father, who is his best friend and presumably a good laugh and a person to chat to, is a paedophile! He has probably been groomed all his life to accept his father's perversions, in that he thinks it's all 'normal' and the child probably wanted it (for money) and dear father is being set up and IT'S ALL NORMAL!
And you would bring your kids (when you have them) to this man? You would allow your Dear Boyfriend to take them to this man, knowing that your dear Boyfriend thinks that even if dear father abuses them, it's either - normal, or it's their own fault?
That is what will happen if you have kids with your bf. They will be exposed to abuse, because your BF and his monster of a father think it's all fine 
IF your BF was repulsed by his monster of a father, IF he went NC with this pig, IF he agreed that NO child should be near him, much less your own kids, then he would not be a lost cause.
But he doesn't. He is almost as bad as his father.
GET OUT NOW!