@LisaRose,
Thanks for your explanation.
My point is, just because someone molests a younger person once (as in the instance you mention) does not automatically mean they become a pedophile or predator. It seems this was the premise the elders were going along with. I am not condoning what happened to your friends child, and it's easy for me to say because it did not involve my children. Heck, if anything like that had happened to my son I would have wanted to scream it from the rooftops, there is no worse wrath than the wrath of a mother. Actually I would have reported it straight to the police...but that's just me. I probably would have warned the sister he was marrying as well.
Presumably if they are still married and all is well with his step children (as I am sure if it wasn't you would have heard about it) it looks like it was an isolated incidence, and if it was, it would go to prove he was not a pedophile and that if your friend would have told everyone that he was it would have constituted gossip.
The problem of pedophilia is very complex, nothing about it is cut and dry as some like to make out...