Young males have been known to view pornography on the Internet. Having a cognitive disability does not necessarily change this behavior. Some kinds of disability, however, mean that discretion can be weak, and boundaries between "acceptable" porn and "unacceptable" porn may not be observed.
That's one reason to try to put some controls in place. Another is that Internet porn is often the equivalent of the sweet smelling sap of a Venus fly trap. It comes with malware, and it can be used to identify a vulnerable population for additional manipulation. A cognitively impaired young person makes a fine catch.
So we have controls -- lots of controls. Not that Apple makes it easy, rumor has Mac Parental Controls are abysmal by design (I so want to kick those engineers). Facebook on the other hand, can be more or less monitored through the User Activity Log. So we've been allowing monitored access, with no password access. In addition to our monitoring, Facebook promises...
Facebook: "Facebook has a strict policy against the sharing of pornographic content ... "
Of course you'll notice they don't say they actually enforce that policy. Thanks to my diligent research assistant I can tell you that Facebook has a diverse and abundant quantity of porn. It appears that the average Facebook porn site lasts a few weeks before it's shut down, but there are always thousands of new sites to fill the gap. I assume the creators are using the Venus Fly Trap business model.
So much for Facebook. The trick then is how to manage the Facebook account - now known to the scum of the earth. In this case I used the User Activity interface to "unlike" the relevant pages (might be useless, but seemed a good cleanup step). Then I used Facebook's obscure Account Deletion page (https://www.facebook.com/help/delete_account) to torch the account.
Sometimes experiments fail. So we take a break and try something different...