This is very typical of what I hear from atheists (the limb thing, easily faked, easily explained away, natural phenomena, people in need of belief, etc).
We just had a thread a couple weeks ago on a canonized saint, that although not a limb, allowed a person to see see with no working eyes.
More dramatic were the events surrounding Giovanni Savino. He and his wife, Rosa, became devoted spiritual children of Padre Pio. In February, 1949, Giovanni was working on an addition to the friary at San Giovanni Rotondo Padre Pios residence. One day, after Mass, Padre Pio blessed him as was customary, but suddenly embraced him exclaiming, Courage, Giovanni, Im praying to the Lord that you might not be killed. Padre Pio repeated this unnerving warning for the next two days. The day following the third warning, February 15, Giovanni and another worker had placed a charge of dynamite under a boulder. When the fuse failed to ignite the charge, Giovanni went over to see what the problem was. The dynamite blew up in his face, which was badly mangled. His left eye was filled with many foreign bodies and his right eye was nothing but a bloody pulp. The doctors felt that they could save his left eye, but determined that nothing could be done for the right one that had been destroyed.
Padre Pio asked everyone to pray for Savino. He exposed the Blessed Sacrament and prayed before It for three days. The friar was even heard to offer one of his eyes for the return of Giovannis sight because hes the father of a family. On the morning of February 25, Savino smelled a sweet fragrance (a frequent accompaniment to the action of Padre Pios intervention). He felt three slaps on his forehead and understood it to be Padre Pio next to his bed. Later that morning the ophthalmologist came to examine his left eye the one he felt he could save. Suddenly Savino exclaimed that he could see. When the doctor asked him to turn his head so that Giovanni could see him with his left eye, Giovanni exclaimed that it was his right eye he could see with. The doctor insisted that the right one had been totally destroyed and that he must be mistaken. However, there was no mistake. Giovanni had completely regained the sight in his right eye, although it remained nothing but a mess until his death twenty-five years later at the age of sixty. The left eye never recovered. Giovanni Savino literally saw without eyes. The ophthalmologist, who was an atheist at the time, converted to the Catholic Faith because, he said, this has happened right in front of me.