With regard to your question concerning spiritual healing:
Such a healing constitutes, indeed, one of the most effective methods of
relieving a person from either his mental or physical pains and sufferings.
'Abdu'l-Bahá has in His "Paris Talks" emphasized its importance by
stating that it should be used as an essential means for effecting a complete
physical cure. Spiritual healing, however, is not and cannot be a substitute
for material healing, but it is a most valuable adjunct to it. Both are,
indeed, essential and complementary.
(From
a letter dated 16 February 1935 written on behalf of Shoghi Effendi to an
individual believer; The
Compilation of Compilations, vol. I, Health, Healing and
Nutrition)