Serious opinions needed about ual abuse a long time ago?

Of course if you confront the Dad he will only deny it. Why would the sister lie about something like that at her age now? If the Dad never contacted his son for 25 years there must have been some reason and that will make a real good story? You are more that likely right about the guilt part. Please make sure he is NEVER ALONE WITH YOUR CHILD. These kind of people never change. They are good at hiding what they realy are, be very carefull around him. Keep a can of Wasp spay around slose by it is better than Mace spray, it has longer reach and just as effective, if you need something like that and it will not effect you as bad. Just for safty. He would think nothing of wasp spray. Good Luck.