Use the free search tool at https://familysearch.org/
Some records shown below, probably many more.
Charles O'Kane and wife Agnes G. O'Toole can be found with their children - in many census'.In 1940 Charles W., J. Bennett and dau Anna are still living with their parents. So no marriage records for them. Richard may have married a 'Louise' - found a Richard O'Kane in Boston in 1940 of the right age - don't know if it's the correct Richard. In early census - not shown - Charles and his Brother Alexander are living together in RI.By 1910 Alexander is living with wife Nellie and her parents Henry and Margaret McLoughlin.
1920 Alex is living with his children (Harry, Annetta, Austin)and Charles and Agnes and their children.No Nellie.
You need to plug all these individual names, birth year/place:(use a range such as 1903- 1905 for someone born 1904.Then expand it a little to 1900- 1909 - as marriage records often do not include birth years at all)to find more info on each individual.
U S Census, 1930 Providence, Providence, RI
headCharles P Okane M 56 IRE wifeAgnes G Okane F 51 IRE dauAnna G Okane F 24 RI sonCharles W Okane M 23 RI sonRichard A Okane M 21 RI sonJoseph B OkaneM 13 RI nieceAnita G Okane F 17 RI nephewAustin J Okane M 15 RI
U S Census, 1940 North Providence Town, Providence, RI https://familysearch.org/pal:/MM9.3.1/TH-1971-27890-2355-8?cc=2000219&wc=MMY7-5W3:n6468
headCharles P O'Kane M 64 IRE wifeAgnes O'Kane F 59 IRE dauAnna O'Kane F 34 RI sonCharles W O'KaneM 33 RI sonBennett O'Kane M 23 RI
R I State Census 1935 Providence, RI https://familysearch.org/pal:/MM9.3.1/TH-267-11779-103074-28?cc=1529126&wc=6887631 (click the forward arrow at the top of this page to see each individual)
O’KaneResidence: 144 Centre St, East Providence, Providence, RI
Charles P O’KaneHead:Family of 6 Male White MarriedRestaurant Mgr. Birth:Jan.13, 1876 Northern IRE Charles W O’kane Male White Single Tobacco Salesman Birth June 20, 1906 RI J Bennit O'Kane MaleSingle WhiteStudent E. Prov HS grade 12 birth date: 19 Mar 1917R I G.Anna O’Kane Single White FemaleTeacher Birth:July 4, 1904 RI G.Agnes O’Kane Married White Female BirthApril 25, 1880Irish Free State A.Richard O’Kane Male White Single Asst Hotel Mgr BirthOct 22, 1908
United States Social Security Death Index first name: Joseph middle name: B last name: Okane birth date: 19 March 1917 social security number: 035-05-8080 place of issuance: R I last residence: Kent, Rhode Island02889 death date: March 1991
Rhode Island, Births and Christenings
https://familysearch.org/pal:/MM9.1.1/F8MY-WF9 Charles O'KaneMale birth date: 20 Jun 1906Providence, R I father's name: Charlesmother Agnes G. O'Toole
https://familysearch.org/pal:/MM9.1.1/F89X-8X2 Richard Aubrey O'KaneMale birth date: 22 Oct 1908Providence, Providence, RI father: Charles O'Kanemother: Agnes O'Toole
https://familysearch.org/pal:/MM9.1.1/F83S-9FP Annie Gertrude O'Kane : Female birth date: 03 Jul 1904Providence, Providence, RI father Charles O'Kane mother Agnes G. O'Toole
Rhode Island, State Census, 1925ED 263 Providence, Ward 06, Providence RI https://familysearch.org/pal:/MM9.3.1/TH-266-12050-236464-8?cc=1532195&wc=5783945
O’ Kane Charles; wife Agnes; dau Anna; son Charles: son Richard; son Bennet;Niece Anita; Nephew Harry
U S Census, 1920 Providence, RI
selfCharles P O'Kane M 43y Ireland wifeAgnes O'Kane F 40y Ireland dauAnna O'Kane F 15y Rhode Island sonCharles O'Kane M 13y Rhode Island sonRichard O'Kane M 11y Rhode Island sonBennett O'Kane M 3y10m Rhode Island broAlexander O'Kane M 39y Ireland NephewHarry O'KaneM 10y Rhode Island NieceAnnetta O'Kane F 9y Rhode Island NephewAustin O'Kane M 5y Rhode Island
US Census, 1910 Providence Ward 9, Providence, RI https://familysearch.org/pal:/MM9.1.1/MP65-LR1
selfHenry A Mcloughlin M 54y IRE wifeMargaret Mcloughlin F 52y IRE dauNellie O Kane F 28y RI son in law Alexander O KaneM 30y IRE Blank nameU y sonHenry A O Kane M 1y 2m RI dauElizabeth O Kane F 0y 0m RI