Help for an 8 year old boy who was sexually abused now fascinated with female's body and sex

I have a friend whose 8 year old son was sexually abused when he was about 4 or 5 and now he was caught sexually acting out with other kids. The other kids parents were informed of the behavior and now the 8 yo is being carefully monitored around other kids. Recently he has been trying to catch his mom and grandmother when they come out of the shower to try and catch them naked. They have noticed him trying to look down their tops at their breasts. He has also been caught by an older female cousin who was sleeping and was awakened by him running his hands up her legs. They can't take their eyes off him for a minute without him doing something such as, fighting with other kids, trying to bully them, or doing something sexual to another child. They have him in therapy but it doesn't seem to be getting anywhere. Is there something else that can be done to help him? He does have a learning disability, at the age of 8 he doesn't seem to be able to read, he's unable to tie his shoes, clean himself well after going to the bathroom, and always have to be given direct instructions when taking a shower. He isn't autistic just seem to have a problem comprehending. Any suggestions would be greatly appreciated to help these people with their child.