Is it obligatory upon the sincere, advising friend to be content with offering advice, or to inform the owner of the trust that was betrayed?

Whoever becomes aware of his Muslim brother's treachery must advise him and explain to him that treachery is not a characteristic of believers. He should urge him to restore rights to their rightful owners and seek forgiveness, and he should not inform those who have been betrayed. An exception to this is someone whose treachery has become frequent and who does not accept advice; such a person must be exposed so that people may beware of him.