Completely forgot all information for Apple ID

My husband had is iPhone stolen recently and has managed to forget everything including the email address he used to create his Apple ID with. Is there a way that he can manage to recover this information from the Apple servers? Since his phone was stolen he changed his phone.l number to a new one but I do still have his old number can we use that old number as a reference to look it up? Need help as he had some items he really needs purchased from the store