The Bechdel Test calls for more than one named female character. They have to have a conversation about something other than the male characters.
We get one and a half. The scene which grabbed that Bechdel pass came when Judy arrived to give Helen a break, as the latter nursed her injured daughter.
They briefly discussed young Karen's health; and Judy reassured Helen that she'd be fine.
In fact, there was an earlier exchange, which might have scored a pass on the test too. Helen was trying to make Karen comfortable and talking in general terms. Her daughter groaned that she was too hot.
But the 'half' conversation came when Helen sat with Barbra. Helen chatted away, trying to win Barbra's trust, but the discussion was one-sided. Barbra was too deeply in shock (or slipping into insanity) for much to be verbally reciprocal. But if we count body language, then communication was achieved.
However none of this means that Night of the Living Dead is a trail-blazing Feminist movie flagship. It serves as an excellent example of the limitations of the Bechdel Test.
None of the female characters are particularly great as role models. Judy simpers and looks lovely, then is so useless that she causes a tragic situation. Barbra goes to pieces from the outset. Helen is slightly better, but her main roles are A Mother and A Wife. While little Karen is comatose for most of the story.
At one point, the men are discussing their escape plan, which is shouted down by Harry. His reason for dismissing it was (I kid you not), "How could we possibly get out of here? We have a sick child, two women and a woman out of her head!"
The portrayal of women in Night of the Living Dead drew so much criticism by Feminists, that Romero eventually re-made the movie. He handed over the directorship to Tom Savini, but was instrumental in guiding that direction.
Barbra was totally rewritten to become a strong female lead. I've not seen it, but apparently it's better from a female representation point of view. It would be difficult to make it worse! Nevertheless, the original Night of the Living Dead did pass the Bechdel Test.