You would each report your share of the proceeds in the investments section of TurboTax and your basis (or cost) would be value at date of death plus improvements you may have made after date of death.

It would qualify and Long Term Capital gain (due to inherited) regardless of how long you held it. 

Make sure all selling expenses are allocated out among you.

To enter your Investments sold

Click on Federal Taxes

Click on Wages and Income

Click on I'll choose what I work on

Scroll down to Investments

On Stocks, Bonds, Other, click the start or update button