This link to a previous topic may be of interestBased on dathai’s suggestion I would consider looking at a Kilkenny cemetery; he had children from his first marriage that died in Kilkenny; or a Dublin military one
FYI (if not already known)
1848 Denis John BOLGER
b. Castlecomer, Co. Kilkenny bap. Jul 10 (F) James (M) Bridget HARDING 
James was a Car Driver at the time of his death on Jan 02 1888 aged 64
James’ daughter Mary WALSH of 58 Charleville Avenue, Dublin was informant
marriage 1 to Mary DEE – cannot find
I think she died Oct 26 1901
marriage 2 Denis BOLGER to Mary WALSH Jan 30 1905 Kilkenny
    Denis’ address Jail Street, Kilkenny (parents’ Castlecomer);
    Mary’s address High Street, Kilkenny (parents’ John & Mary CONNERS Inistioge)
Children of Denis John BOULGER and Mary DEE
1.   1881   Sarah Harding BOLGER b. Harley Wintney, Hampshire Q- V2c P181    
edited to add    She was granted outdoor relief of 4/= per week on Aug 9 1911
    based on an application from her step mother who was "unable to keep her, having two other step-daughters"
    Subsequently Sarah was admitted to the Dublin Workhouse (shown on the in-house relief register)
    on Oct 14 1911 from 62 Dominick Street
    and discharged to home on Mar 21 1912; however it does not give an address then
    She was admitted to the Dublin Workhouse again (shown on the in-house relief register)
    on Jan 08 1914 from 8 Shanganagh Road, Drumcondra
    and discharged to Cabra Institute (for the Deaf and Dumb) on Jul 11 19162.   1883   James Dee BOULGER b. Stoke Damenel, Devon Q1 V5b P341
    Shown on 1911 census in UK in 1st Battalion Royal Irish Regiment
    as born in Kilkenny
    possibly married Julia C BOLGER 1920 Kings Norton 
3.   1885   William Patrick b. New St., Kilkenny
    DoB Feb 07 1885; DoBap Feb 12 1885
4.   1887   Mary Florence b. Ormond St., Kilkenny
    DoB Jan 23 1887; DoBap Jan 24 1887
   died aged 9 months Sept 9 1887
5.   1888   Denis Francis b. Ormond St., Kilkenny
    DoB Aug 12 1888, DoBap Aug 18 1888
   joined Royal Irish Fusiliers in 1903 at 15 with a consent letter from father;
    address for family shown as Gaol Street, Kilkenny
6.   1890   John Joseph b. Ormond St., Kilkenny
    DoB Apr 20 1890; DoBap Apr 25 1890
   died aged 5 months Sep 18 1890
7.   1891   Maria Maude b. Ormond St., Kilkenny
    DoB Sep 13 1891; DoBap Sep 23 1891
   married John William MOORE Sep 03 1918 St Columba’s Drumcondra
8.   1893   Edith Victoria b. Ormond St., Kilkenny
    DoB May 16 1893; DoBap Jul 09 1893
   married Joseph RYNELL Sep 01 1917 St. Catherine’s Birmingham
9.   1896   Bridget Josephine b. Ormond St., Kilkenny
    DoB Sep 01 1896; DoBap Sep 03 1896
   died Oct 17 1900 aged 4 years and 2 months
10.   1899   Margaret Mary b. Ormond St., Kilkenny
    DoB Oct 30 1899; DaBap Nov 06 1899
   married Gordon F Taylor Jul 4 1928 St Joseph’s Tung T’ang Peking
In 1903 on Denis Francis’ army record, he is shown as having six living siblings; brothers James and William; sisters Sarah, Maria, Edith and Cissy (presumably Margaret)