Capital Gains work differently on estates in Canada than USA. There is no stepped up basis on death / inheritance of property before taxes are paid. (excluding some spousal rollovers and Trust situations WRT taxes, but never a stepped up basis without taxes)
This following will depend on if the deceased were american or canadian... but the canadian side would look like this:
1) Property Fair Market Value - Actual Cost Base is determined. (Total increase in value)
2) Capital gains is this x 50% (per normal)
3) The estate pays the capital gains at the deceased person's marginal tax rate on their final return. If there is not enough Cash to pay it, the property or something else needs to be sold to pay the taxes, or the heirs provide cash to prevent a sale.
4) The property is allocated to the heirs. No tax to the heirs. Inherit at the current FMV.
If the deceased is a US citizen, it looks the same, except they would have TAX WITHHOLDING at the US / Canada rate (starting at 15%). .. E.g., their estate needs to pay the with holding tax of 15% (or more) on 50% of the gains to Canada.
Then, the estate files the final tax return for the deceased, and claims a FOREIGN TAX CREDIT on the IRS form, in the amount paid to the CDN government, so no double tax.