How long ago did it happen? I doubt that it is too late to prosecute, as many children don't report sexual abuse until many years later, and it is still prosecuted at that time. Finding enough evidence might be a challenge.

It is good that he was finally able to tell you. Now he can start to heal. You must be in turmoil though. I know that you will do the right thing.

Take Care - both you and your family,
Rap