Is money earned from a cafeteria that serves tea, coffee, food, and shisha unlawful? And is it forbidden for one's family to partake of it, knowing that if mixed money's lawful portion is greater than its unlawful portion, then it is permissible to spend from it?

It is not permissible to participate in purchasing a share in a cafeteria that offers forbidden items. The profit from this cafeteria is mixed money, and it is obligatory to dispose of the unlawful portion of it, while the remaining portion is permissible to benefit from. However, this does not remove the sin of participating in a forbidden matter. Intentionally earning unlawful gain is not permissible.