I found this memorial on Find a Grave... you may be able to contact the creator of the husband's memorial as they have taken the time to link all the children to the memorial.
I would bet that this person would have the information you seek.
The Find a Grave memorial lists the place of death as Grayson County.
http://tinyurl.com/km28z4w I will still see if I can find out what cemetery was used. The memorial shows that she was buried at the Little Clifty Methodist Cemetery in Grayson County.