By the Islamic law of inheritance (mīrāth) there is no transfer between a Muslim and a non-Muslim: the Prophet ﷺ said, "A Muslim cannot be the heir of a disbeliever, nor can a disbeliever be the heir of a Muslim." So under the Islamic shares you are not your non-Muslim parents' heir. However, most scholars permit you to accept money your non-Muslim relatives leave you as a bequest (waṣiyyah) or give you as a gift, since that is a gift rather than Islamic inheritance; a minority of early scholars even held that a Muslim may inherit from a non-Muslim relative though not the reverse, while the four madhhabs hold there is no inheritance either way — so if this actually arises, put your exact situation to a trustworthy scholar. For your own estate, since your non-Muslim relatives are not Islamic heirs, you may leave them up to one third by bequest: when Saʿd ibn Abī Waqqāṣ wanted to will away half his wealth the Prophet ﷺ said, "One-third, yet even one-third is too much." None of this affects your duty to be kind, generous and dutiful to them while they live — Allah explicitly permits and encourages dealing kindly and justly with those who do not fight you over your religion.
Q&A · New Muslim
Can I inherit from my non-Muslim parents, or leave them something in my will?
Evidence — the daleel
On deen2u
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.