How should he deal with his wife who is mentally ill?

Praise be to Allah.

We appreciate your confidence in us, and we ask Allaah to guide us all to the right path. 

I have read your letter more than once and I feel that it is difficult for me to understand the issues properly, because it seems to be somewhat complicated, so I cannot blame one of you. But I feel that both of you have some share of blame for the problem.  

But I can offer the following advice and suggest that you do these things, and I ask Allaah to make this a help for you in solving your problem. 

Firstly:

Each of you must come back to Allaah because sin has an effect on people’s family lives and on all their relationships. Hence one of the salaf said: when I commit sin, I see its effect on my family and my riding-beast. This confirms what the Prophet (peace and blessings of Allaah be upon him) said, according to the hadeeth narrated by Abu Hurayrah who said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “When Allaah loves a person He calls Jibreel and says, ‘I love So and so, so love him.’ Then Jibreel loves him, then he calls out in the heavens saying, ‘Allaah loves him, so love him.’ Then the inhabitants of heaven love him, and he also finds acceptance on earth. But if Allaah hates a person, He calls Jibreel and says, ‘I hate So and so, so hate him.’ Then Jibreel hates him, then he calls out in the heavens saying, ‘Allaah hates So and so, so hate him.’ So they hate him, and he is also hated on earth.” 

Secondly:

Each person must turn towards his Lord and call upon him. Allaah Says (interpretation of the meaning): 

“Is not He (better than your gods) Who responds to the distressed one, when he calls on Him, and Who removes the evil”

[al-Naml 27:62]

So he must persist in du’aa’, and seek out the times when du’aa’ is more likely to be accepted, such as the last third of the night, when our Lord descends and calls out, “Who will call upon Me, that I may answer him; who will seek My forgiveness, that I may forgive him; who will ask of Me, that I may give to him; who will repent to Me, that I may accept his repentance?” So you should call upon your Lord and have certain faith that He will respond, but do not try to hasten the response, for Allaah will respond to His slave so long as he does not try to hasten the response and does not say “I made du’aa’ but I received no answer.” 

The Prophet (peace and blessings of Allaah be upon him) said: “Allaah has not sent down any malady but He has also sent down the remedy; those who know it, know it, and those who do not know it, do not know it.” (Narrated by Ahmad, 3397; classed as saheeh by al-Albaani in al-Silsilah al-Saheehah, 1650). So you must recite the du’aa’s that are prescribed in sharee’ah, such as ruqyah, reciting Qur’aan, etc. Allaah says (interpretation of the meaning): 

“And We send down of the Qur’aan that which is a healing and a mercy to those who believe”

[al-Isra’ 17:82]

If she refuses to be checked out by a psychiatrist, then there is nothing wrong with your trying to mediate between them. 

Fourthly:

What your wife needs most from you is that you should be warm and loving towards her. For example, take her for a drive in the car to a place that is calming and soothing to the nerves, or take her on a trip to another city. Insist kindly on taking her out if she refuses and choose activities that she is accustomed to and that she likes, such as going to a place that she likes or letting her do some of her hobbies. 

Fifthly:

Do not be forceful if she refuses to cooperate, because for the one who is depressed  you can draw attention to things but you cannot demand him to do things, because that will increase his feelings of failure. 

Sixthly:

I advise you to be kind and gentle, for there is no kindness in a thing but it adorns it . 

Finally, you should note that the person who is suffering from depression is lethargic and is not interested in improving his situation, such as trying to recover from depression by himself. Remember that most cases of depression can be dealt with but it may need a long time and goodly patience. Remember that you may be one of the causes of her illness, so do not rush to end the relationship.  You have to help her to get out of the situation she is in, and remember that no matter how difficult it is to be patient, the results will be good,

And Allaah knows best. May Allaah send blessings and peace upon our Prophet Muhammad and upon his family and companions.