The CBC's Fifth Estate is a very respectable and credible television production.
The elder/lawyer would have been checked out for validity before being included in the broadcast. As far as his anonymity goes, isn't that to be expected and isn't it also to be respected rather than rejected? Not everyone is in a position that allows them the privilege of having an identity.
Protecting the identity of whistle blowers is a fairly standard practice. And more common than not when a television expose is done on sensitive material concerning a large corporation and/or religion.