When you get to “Mother” in the Guitar Accompaniment Book from OCP (c2005) you have to expect hymns to the BVM.
OCP says this one is from a collection called Wreath of Mary from 1883 and is set to traditional tune OUR LADY OF HELP. They omit the third verse noted here. You can purchase their sheet music here.
Mary at Godsongs has researched other possible origins and has a fourth verse.
Mother dearest, Mother fairest,
Help of all, who call on thee.
Virgin purest, brightest, rarest,
Help us, help, we cry to thee.Lady, help in pain and sorrow,
Soothe those rack’d on beds of pain,
May the golden light of morrow,
Bring them health and joy again.Lady, help the absent loved ones.
How we miss their presence here.
May the hand of Thy protection
Guide and guard them far and near.Chorus
Mary, help us, help we pray.
Mary, help us, help we pray.
Help us in all care and sorrow.
Mary, help us, help we pray.