Found this:

Robert Joseph Blair married Adeline Chouinard on 9 august 1864 in Lotbiniere, St-Eduard. He was the son of David Blair and the late Caroline
and Adeline was the daughter of the late Oliver Chouinard and Archange Vaillancourt

children listed in same parish
Marie Jeanne Elise Blair, bap on 8 Dec 1865
Marie Flore Blair, bap 16 Dec 1966
Joseph Albert Blair, bap 16 July 1868
Marie Anne Blair, bap 25 Sep 1870
Marie Caroline Alice Blair, bap17 Dec 1871
Joseph Hugues Blair, bap 23 July 1873
Joseph David Blair, bap 25 Dec 1874 Died 1 Sept 1875
Joseph David Blair, bap 12 Aug 1876

No other children listed.

Adeline Blair, age 59 remarried on 6 Mar 1905 in Manchester, New Hampshire to Edmond Blais age 60. Her parents were Oliver Chouinard and Agnes Vaillancourt, his Louis Blais and Scholastique Bernier.

Other children may have been born after the birth of Joseph David, but I don't know where they are at that time. Adeline stated she immigrated in 1880, but they are listed in the 1881 Canadian census. Find no record for Robert's death in NH records or in Quebec.

Other children could have been born and died in a different place, or miscarried. But there are more listed here then the original 6 so I hope it helps.