You use the 1099-B worksheet even if there is no 1099-B.  Then you enter the nondeductible loss as the "adjustment amount" with a code L for the "adjustment code."  It should come out as zero gain or loss.  At least that's how I would do it, it's not worth spending a lot of time on because I'm not the one she favored with her generosity.

I'm not saying she needs to do a gift tax return because you didn't ask about that.