How to Treat Mental Illness

Q: We had an elder brother who was committed to his religious affairs: prayer, fasting, performing the lesser pilgrimage, reciting the Qur'an, maintaining the congregational prayer in the mosque, and attending the circles of dhikr. Suddenly, his condition changed, and he stopped praying, stopped reading the Qur'an, and stopped attending the circles of dhikr. He became someone who sits alone in his room, to the point that he does not even go to his work. Please advise us on what we should do regarding our eldest brother—may Allah reward you with good?
A: It is prescribed that he be treated with Prophetic medicine and with the treatment known by specialized doctors, provided it does not contradict the pure Shari'ah. This is based on the saying of the Prophet (peace and blessings be upon him): and his saying (peace and blessings be upon him): which Muslim recorded in his Sahih.
And his saying (peace and blessings be upon him): And among the lawful remedies is reciting over him by people of knowledge and faith, so that perhaps Allah may benefit him through that.
Among the beneficial causes for this and similar cases is referring him to specialized doctors who are people of faith and piety, so that perhaps they may know the cause of his illness and its cure. May Allah heal him from what has befallen him, and may He assist you in treating him with what benefits him and through which Allah reveals his illness, for He is Generous and Bountiful.