Bernard and Joseph's Father or possibly Parents left Ireland in or around the famine times from a village called Kesh in Co Fermanagh – now in N Ireland

They moved to England near Bermondsey, London
MacMenamin Origin in Ireland to Bermondsey, London during Potato Famine

Who's Who
Celtic who's who names and addresses published 1921
MACMENAMIN, John. (Seaghan MacMeanman.) 
    Address — Kingarrow, Lough Finn, Co. Donegal. 
    Born 30th Oct., 1887. Father, Peter MacMenamin : Mother, Mary MacMenamin. 
IDEA - if we can find Joseph's death certificate, since we know he died in Dublin Ireland, then maybe it will state the names of Joseph & Bernard's father.
Winner of gold and silver medals in Literary 
Competitions Oireachtas (1910 ; winner of gold Cross, Springfield (Mass.), Irish Literary Society (1911). 

Publications— Sgeulta Goiride Geimhridh (1915); Contributor, over various nom-de-plumes, of articles 
and stories of Irish interest to Irish-American papers.