Therapist claims its "normal". Please read on. . . . .?

So here is the situation, there are 2 boys, 11 and 6. The eleven year old is getting curious about , which is typical at that age, I am aware. A few months ago, he was caught trying to his brother, both being naked, he claimed he couldn't get it in. So therapy began, in house and at the Dr.'s office. Well they were caught doing the same thing the other day, and the therapist claims its "normal". How is trying to molest your brother normal??? Does anyone have any answers? As well as a few weeks ago, there was a situation with his sister, which we don't know all the facts. But if this is so "normal", maybe I'm not because it has never happened to me. I am just disgusted by the entire situation, and for everyone to think its normal, in my eyes is a crock of ****!! I don't have a direct question here, except to wonder what you think. They aren't family of mine, but nephews of someone who I am very close to. And what happens next time, pat him on the back, its normal