The detail of this story proves a folk rather than a literary source.
The story has three parts. (1) The, foolish brother kills his mother in the bath. (2) The two brothers hide in a tree under which robbers are dividing their spoil and frighten the robbers
away by dropping down a weight upon them. (3) One robber returns, and gets his tongue cut out.
Compare Zeltner, 62-72; Arcin, 477; Lenz, 51-53; Parsons, Andros Island, 92-94 and reference note; Sea Islands, 132; Espinosa, JAFL 27:119-120; Recinos, JAFL 31:473-474.
(1) See Grimm 147, Old Man Made Young Again, Bolte u. Polívka 3:193-199, where the killing hot bath is identified with the fire bath which restores the old to youth, but which either fails when attempted by a pretender or is employed as a trick to destroy a powerful enemy; e. g. Ferrand, Madagascar, 67. In Arcin and Zeltner, the story follows this order: (1) Gold-producing animal, (2) Life-giving staff, (3) Ear cut off, the life-giving staff taking the place of the killing hot bath. In a Jamaica version from Richard Morgan, the killing hot bath is followed by the story of carting the mother about as if she were alive and extracting hush money from her pretended murderers, as in number 135 (episode G" in Bolte u. Polívka's analysis of Grimm 61).
(2) and (3) See Grimm 59, Frederick and Catherine; Bolte u. Polívka 1:520-528.