They said, He became sick because he is religious

Question :

A man from our city who adhered to the precepts of the religion suffered from a mental disorder. Some people said that he became sick because of the religion. And because of what he heard from people, he shaved his beard and he no longer prays regularly. Is it permissible to say that he became sick because of his adherence to the regulations of the religion? And when a person says something like this, is he a disbeliever?

Answer:

Adherence to the religion is not the cause of any sickness; rather, it is the cause of all that is good in this world and in the Hereafter. It is not allowed for anyone to follow those who are foolish if they say things similar to this. It is not allowed for him to shave his beard, to trim it, or to stay away from prayer in congregation. It is incumbent upon him to remain steadfast upon the truth, and that he stay away from all of what Allah prohibited him from and His Messenger ﷺ and being wary of what angers Allâh and causes His punishment. Allah Almighty said:
"And whosoever obeys Allah and His Messenger will be admitted to Gardens under which rivers flow (in Paradise), to abide therein, and that will be the great success. And whosoever disobeys Allâh and His Messenger, and transgresses His limits, He will cast him into the Fire, to abide therein; and he shall have a disgraceful torment."

He also said:
"Whoever fears Allâh and keeps his duty to Him, He will make a way for him to get out (from every difficulty). And He will provide him from (sources) he never could imagine."

And:
"Whosoever fears Allah and keeps his duty to Him, He will make his matter easy for him."

As for the one who said that the illness that struck him was because of his adherence to the religion, then this person is ignorant. It is required to reprimand him and he must be taught that adherence to the religion only results in what is good, and that when a Muslim suffers from something that distresses him, this only means that his sins and mistakes are being atoned for. As for calling such a person a disbeliever, this question requires a detailed answer, which may be found under the topic of apostasy in the books of Islamic Jurisprudence. And with Allah is the facilitation to do what is right.

Source:
Ibn Baz
Fatawa Islamiyah, Vol. 8 Pages 309-310-311