He found out after marriage that his wife is mentally ill. Should he ask for the mahr to be returned?

Dear Brothers & Sisters,
As-Salaamu-Alaikum wa Rahmatullahi wa Barakatuh. (May Allah's Peace, Mercy and Blessings be upon all of you)
One of our brothers/sisters has asked this question:
I married and later on I discovered my wife has psychological problem. Her other sister are ok. They only agree to have MEHR_Missal at that time (as I do not about her problem). I already give her MEHR.
Under such condition what MEHR suppose to be. I feel is a total fraud.
Is Mehr suppose to be justified again?
Although, I am on terrible road of marriage life.
It is probably possible that (if there is a separation) she can use that same MEHR money against me by hiring good lawyer and get most out of the USA law (against me). What I can do in this situation?
Jazakallah Khair!
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Check below answers in case you are looking for other related questions:
The mahr (dowry) is the right of the wife
He wants to take her back on condition that she give up the furniture that he put in her name

Answer:

Praise be to Allaah.

Refer to a sharee’ah judge (qaadi) if there is any qaadi there. If not, then if the man has consummated the marriage with the woman, the mahr must be given to her because of having had intercourse with her. As for this sickness, if it prevented him from consummating the marriage or put him off from doing that properly, then whatever was paid to the one who tricked him into this marriage should give it back, if he was tricked. If that is not the case, then he does not deserve anything because he did not ask enough questions and find out information properly.

Whatever written of Truth and benefit is only due to Allah's Assistance and Guidance, and whatever of error is of me. Allah Alone Knows Best and He is the Only Source of Strength.
Your brother and well wisher in Islam

Related Answers:
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