Praise be to Allah.
Parties should not be mixed; it is necessary for there to be parties for men only and parties for women only. Mixing is an evil action and is one of the ways of the people of jaahiliyyah (ignorance) – we seek refuge with Allaah from that.
With regard to healing through music, there is no basis for that, rather it is the action of the foolish. Music is not a healing, rather it is a disease and is based on the use of forbidden (musical) instruments. All of that is a disease of the heart and a cause for deviation of morals. The beneficial treatment which will bring peace to the soul is for the patient to listen to the Qur’aan and useful speeches and sermons. Treatment with music and the like is something which makes people get used to falsehood and makes them more sick, and makes them listen to the Qur’aan and Sunnah and useful preaching even less. There is no strength and no power except with Allaah.