The stock is long term. That is the easy part. You can put any date for stock acquired as long as the date is more than a year before the sale or choose “inherited “ from the drop down menu. The hard part is determining the cost basis. You could make a good faith effort to arrive at it by researching what you think is a reasonable average price about the time it was gifted. Google historical stock prices for sites that offer that information. If the IRS challenges it, your basis will be zero.
