disown
verb
To refuse to recognize or acknowledge: deny, disacknowledge, disavow, disclaim, reject, renounce, repudiate. Idioms: turn one's back on. See accept/reject.

Seems to cover it for me
Yes I know all that but IMHO it is still a damn silly expression ~ and overuse in this context makes me think two things. That the sons are busy organising their own lifeboat and secondly that it is being bandied about purely for dramatic impact, which it will rapidly not have if they keep it up.
Mrs S#1 used to frequently fall out with members of her family and would announce that she was "Washing her hands of them" ~ again I understood what she meant but I still felt that to be a silly phrase as well ~ particularly as she said it so often of so many that (i) it lost all impact and (ii) she must have had the cleanest hands in the country.