Each property sale is reported separately in the Stocks, Mutual Funds, Bonds and Other interview under Investment Income. Both would be considered "second homes" or "inherited homes".
The cost basis for each house would be the fair market value (FMV) of the house at the time of your mother's passing.
For instructions on making the entries, see Where do I enter the sale of a second home, an inherited home, or land on my 2019 taxes?
And, our sincere condolences for the loss of your mother.
