Edward McGrath b. 1839

for reference the baptism was in the Catholic parish of SS. Michael & John RC, the SS. stands for Saints, which had a church on Lower Exchange Street in South Dublin City, although close to the Liffey. The parents are recorded as Peter McGrath and Anne and sponsors (godparents) as John & Mary Coniff... unfortunately no mother's maiden surname is recorded making it difficult to be certain of any siblings or the parents marriage.

Does your friend know where this Edward married ?
If so his marriage might include his mother's name, many of the later Catholic parish marriage include names and residences for both parents.

located a marriage which might fit - and Edward McGrath married Catherine Murray on the 17th August 1862 at St. Mary's RC Parish (Pro-Cathedral, Marlborough St.) in Dublin North City. Edwards parents are shown as Peter and Anne McGrath, no surname given for Anne. The groom's residence is given as 49 Jervis Street, and his parents both seem to be alive at the time, and also living at the same address. The bride's residence is also 49 Jervis St., and her parents are Jeremiah & Mary are living at Constitution Hill. The witnesses are John Smith of 24 Stafford St. and Mary(Maria) McGrath living at 49 Jervis Street - maybe a relative of Edward ?