since she owned and lived in it for 2 out of the 5 years before sale, $250,000 of the gain is totally excluded from income (home sale exclusion). some other items that will reduce the taxable gain:
that $250K increases to $500k if she was married and her husband died within two years of the date of sale and occupied the house 2 of 5 years before sale.
1) sales expenses
2) capital improvements. in 60 years certainly some capital improvements were made
3) if she inherited part or total ownership of the house there would be a step up in basis for this
so without knowing anything about the items above the taxable gain would be less than $450,000
about the first $45K is taxed at zero
the next $405K is taxed at 15% ~ $60K in taxes
in addition, since the gain on the home sale is treated as investment income and exceeds $200K
adjusted gross income of the $250K gain and $13K of other income (i assumed it was social security of which 85% would be taxable) is subject to the net investment income tax of 3.8% about another $10K in taxes.
so ~$70K in federal taxes but it certainly should be less considering the items cited above
state taxes were not considered.
