John Newton's "The Prodigal Son" (in Olney Hymns, vol. 1, 1779) is HERE. PRODIGAL SON (Tune: E. J. King, 1844; Lyrics: John Newton, 1779) is in The Sacred Harp (CLICK HERE). TENESSEE (Baptist Harmony, p. 227) is in Southern Harmony (CLICK HERE.
There are four tunes to "Afflictions though they seem severe" in George Pullen Jackson's books.
(1) TENNESSEE (Hesperian Harp 140). In Spiritual Folk-Songs of Early America, no. 24. The words are almost identical with those Jean posted.
(2) PRODIGAL (Supplement to the Kentucky Harmony 35). In SFSEA, no. 49.
(3) RETURNING PRODIGAL (Southern and Western Pocket Harmonist, 1846, p. 140). In Another Sheaf of White Spirituals, no. 109.
(4) PRODIGAL'S RETURN (Wesleyan Psalmonist, 1842, p. 8). In ASWS, no. 110.
~Masato