the ethics rule bus, that now has cause to disbar him for acting on a client's behalf, without the client knowing...
There is no such rule.
Just because you don't know the law, doesn't mean there is no law.
https://www.nysba.org/DownloadAsset.aspx?id=50671
NEW YORK RULES OF PROFESSIONAL CONDUCT Effective April 1, 2009
Rule: 1.4 Communication.
A lawyer shall: (1) promptly inform the client of:
(iii) material developments in the matter including settlement or plea offers.
(3) keep the client reasonably informed about the status of the matter;
Communicating with Client [2]
In instances where these Rules require that a particular decision about the representation be made by the client, paragraph (a)(1) requires that the lawyer promptly consult with the client and secure the client’s consent prior to taking action, unless prior discussions with the client have resolved what action the client wants the lawyer to take. For example, paragraph (a)(1)(iii) requires that a lawyer who receives from opposing counsel an offer of settlement in a civil controversy or a proffered plea bargain in a criminal case must promptly inform the client of its substance unless the client has previously made clear that the proposal will be acceptable or unacceptable or has authorized the lawyer to accept or to reject the offer.