Is it permissible to direct Zakat funds, vows, or charitable donations towards treating patients in a general hospital, or for contributing to the construction and equipping of a hospital that treats Muslims and others, with the intention or condition of treating only Muslims, or to spend the money for another purpose?

It is not permissible to spend zakat funds on building hospitals because the legitimate recipients of zakat are specified in the Quran. However, it is permissible to give voluntary charity (sadaqat al-tatawwu') for building or equipping a hospital to treat Muslims and others, with the permissibility of intending that the treatment be for Muslims only. As for vows (nadhr), if a vow is made to a specific person or a known entity, it must be fulfilled for that person or entity. If it is not made to anyone specific, then it is permissible to spend it only on treating poor Muslims.