Bless you, Mercat!
I recently heard a similar story of someone asked to pray for a Protestant friend, who was dying. Recalling the words of our Lord to St. Faustina:
"....When they say this Chaplet in the presence of the dying, I will stand between My Father and the dying person not as the just judge but as the Merciful Savior".
She began praying the Divine Mercy Chaplet. Like your friend, the dying woman was most agitated but as soon as the Chaplet prayers began, she quieted down immediately. Nearby, a Protestant family observed the dramatic change in this woman's composure, listened to the Chaplet and later inquired about these prayers. Should you return to this dying woman's bedside, you may want to include the Divine Mercy Chaplet, as well. Combined with the Rosary, these are most powerful prayers!
thanks. I'll google it.