Election Board of New York is looking in the matter and has not released any statement on the issue till date.
They also claimed another such incident occurred when Gertrude Nizerre, who died on Jul. 4, 2016, requested an absentee ballot in September with an address in Brooklyn. But her ballot was declared invalid on Oct. 30, after discovering that the voter was dead.
The Board of Elections told New York Post that it was looking into the matter. Filling out a ballot in a dead person's name is fraud and has resulted in prosecutions. They also said absentee ballots don't get counted until six days after Election Day in New York.
Due to the lack of evidence, this claim is unverifiable. We also tried to reach out to the New York City Board of Elections office but received no reply. Furthermore, the claim of 'dead people voting' was made with regards the wider, baseless claims around widespread voter fraud. However, one incident with absentee ballot does not amount to widespread voter fraud.