What is the ruling on searching the room of a person who is an alcoholic, does not pray or fast, and supports the secular state, and taking some of his trivial belongings without his knowledge, out of hatred?

It is not permissible for a Muslim to take what is unlawful for him through transgression, theft, embezzlement, or usurpation, and this applies to everyone. Whoever has taken something must repent, seek forgiveness, and return it to its owner, even if indirectly, as this is one of the conditions of sincere repentance. Likewise, one must repent and seek forgiveness for meddling and searching through others' belongings without their knowledge.