Is it permissible to take financial compensation for doing homework assignments for foreign students? Is the money earned from this considered unlawful? Does the ruling differ if the students are taught for their academic benefit, taking into consideration the person's need to cover their postgraduate study expenses?

If the intention is to complete students' homework assignments for them to submit as if they had done them, then this is impermissible deception (ghishsh). As for helping students understand lessons for a fee outside of regular working hours, this is permissible under certain conditions.

Money earned from a prohibited act, such as deception (ghishsh), is unlawful money (mal haram), and it must be disposed of by spending it on general Muslim welfare (masalih al-muslimeen al-'ammah) or distributing it to the needy. It is not permissible to benefit from it. What was spent before knowing of its prohibition is excused.