The following is correct based on some searches today, with civil references fyi
Link to details on Elizabeth BRENNAN you are proably aware of
This piece is quite clear in her birth being 1907 in Co. Tipperary and details her works with dates from 1946 up to 1984
In 1946 she would have been 39 years old would Brennan have been her maiden, first married or second married name?!
You could apply for the death cert of the person named on the grave
i.e. Elizabeth Brennan died Oct 02 1993 to establish her age and if she was married etc.
The fact that Robert Hale had the same place as her last address looks promising
Patrick Victor POWER was born 1930 Dublin South Q4 V2 P433 died 1988
was the brother of writer Richard POWER born 1928 Dublin South Q1 V2 P490 died Feb 12 1970 Ravenna, Convent Avenue, Bray, Co. Wicklow;
1987 article in the Dungarvan Leader see page 6:
LINKand possibly another brother was
Louis M G POWER born Dublin South 1930 Q4 V2 P434
(Louis POWER is the name of the person to whom probate was granted on Richard's Will)
Their parents Patrick J POWER and Kathleen M MURPHY married in 1926 Dublin South Q3 V2 P481
leading me to believe that Kathleen BRENNAN was not their sister.
She may have been their aunt.
As you can see in the article, Victor's uncle William POWER m Jane ORPEN in 1947
(it states 1946 but it was in Kilmacthomas 1947 Q4 V4 P264)
Jane was distantly related to William ORPEN seemingly
There are articles on line referring to Victor's teaching career in the US, one of which
LINK refers to his aunts writing to him, asking him to come home to Ireland which implies there were some!
There is a tree online with an Elizabeth BRENNAN b1907 d 1981 in Castlecomer, Co. Kilkenny married to John William CASEY b. England 1901 d 1979 Castlecomer, Co. Kilkenny; both shown as on October 12th