It appears that Thomas McVeety (b.1820) and Margaret McTavish (b.1819) had four children.
The eldest child was Mary McVeety (b.1842) who apparently did not marry and died 19 April 1909 in Lanark County, Ontario.
The second child was Thomas X. “Short Tom” McVeety (b. 8 Aug 1846) who moved to Polk County, Minnesota, married Isabella McDonald, had seven children, and died 11 Feb 1913.
The third child was James McVeety (b.1848) who married Elizabeth Megraw, had six children, and died 5 Oct 1913 in Bruce County, Ontario.
The fourth child was Margaret McVeety (b.1853) who married John Anderson, had six children, and died in 1897 in Toronto.
My records show that Margaret McTavish died in 1848 and that Thomas McVeety (b.1820) remarried in 1860 to Agnes Hunter. The 1848 date cannot be correct, however, because her fourth child was born in 1853. (I’m not sure of my source. Perhaps the death date was 1858. That would make more sense.)
You mentioned in an earlier post that you have a 1900 photo of your grandmother Helen and her sister Jean along with an older woman identified as “Mary McVeety.” I suspect that the older woman was their Aunt Mary McVeety (b.1842), who would have been about 58 years old at the time.