Hi, I was wondering where you got the copy of Alexandre's death record -- perhaps his birth and marriage records would be on the same source??
There really isn't much in the census records for Nova Scotia on the name "Charpentier" -- I believe that the name was anglicized in the early 1800's. This is what I have found by just searching on Ancestry:
1817 Canadian Census Records:
1) Alexander Carpenter living in Harbour Boucher
2) Lewis Carpenter living also in Harbour Boucher
3) Michael Carpenter living in Little Harbour and Tracadie
1871 Canadian Census Records:
1) Alexander Carpenter b. 1796 wife Nanette b. 1797
2) Michael Carpenter b. 1799 widower
3) Louis Carpenter b. 1803 wife Marina
There is a death record for a Lewis Carpenter, Sr. in 1867 who died at the age of 85 years which would have his approximate date of birth in 1782. His father is listed as George Carpenter. There is also a widow Jane Carpenter b. 1788 who may have been Lewis, Sr.'s wife -- she is living with a family of Levandiers.
All records for the individuals listed above indicate that they are French Catholics.
I don't know if any of this helps but if Alexander and Lewis, Sr., were brothers, then perhaps their father was a George/Georges Carpenter/Charpentier.
Hope I haven't made the mystery deeper!! Happy Holidays!!!
Jane