Does a person become an infidel if he blames his mother for causing his phone to get dirty – a phone he had washed fearing it would be damaged – believing that the situation would have been different had a problem not occurred between her and his brother, and is he required to inform those who heard him say that?

Instead of occupying oneself with self-condemnation, one should occupy oneself with pleasing one's mother, for honoring one's parents is one of the greatest expiations for sins. Al-Marwazi narrated from Imam Ahmad that honoring parents is an expiation for major sins. The statement "If only I had done such and such" is forbidden because it expresses objection to divine decree, and the Prophet, peace and blessings be upon him, forbade it, saying: "It is the decree of Allah, and what He willed He did. For 'if only' opens the way for the work of Satan." This statement does not amount to disbelief, and some scholars interpreted the prohibition of "if only" as a recommendation to avoid it rather than an absolute prohibition, especially if it does not involve discontent. Discontent itself is not disbelief. Repentance is not required in front of those who heard you; rather, repentance is for Allah alone. It appears that the questioner is suffering from obsessive doubts, and is advised to supplicate and consult a trustworthy psychiatrist.