When Jesus saw his mother* and the disciple there whom he loved, he said to his mother, “Woman, behold, your son.”  Then he said to the disciple, “Behold, your mother.” And from that hour the disciple took her into his home.

St John was the beloved disciple.   He was there. 

If Monica is to be believed...that the synoptics are the only Gospels where concrete facts can be found....and St John's is merely symbolic (she misunderstands the full nature of the Gospel, and she likely misunderstands the difference between sign and symbol as well) then it follows that NOT EVEN MARY The mother of Jesus was at the foot of the cross.

See for instance the notes at the USCCB website, with respect to the Gospel of St John: 

"Only John mentions the mother of Jesus here. The synoptics have a group of women looking on from a distance at the cross (Mk 15:40)."

http://www.usccb.org/bible/john/19