Most cemetery statues do not look like any particular person associated with the deceased. They might resemble a model the artist used, but they are not meant to be representative of a particular person. On the other hand, people recognized this statue when it was placed.
This is Mary Lowry. She was so distraught at the death of her husband Joseph that she had a statue made of herself to mourn at his grave until she joined him there herself.
I’m pretty sure this last shot is the marker for the Mary Lowry who had the statue commissioned, but I haven’t been able to confirm it.