What is the ruling on residing in a house where sacrifices were offered to other than Allah, and is the money inherited from a grandfather who sought help from jinn and accepted offerings considered lawful or unlawful, and is it permissible for the heirs to take it, especially since the parents live alone and rely on this money?

The money received by the grandfather as a gift is permissible for him, and it is permissible to reside on the aforementioned land, and it will be inherited from him. However, if it was an offering presented to a created being as an act of drawing closer, then it is not permissible to own it or inherit it; rather, it should be spent on charitable causes. If there is doubt about its amount, the unlawful portion should be estimated and disbursed through ijtihad (independent reasoning). Abstaining from this money out of piety is good, but one should not make things difficult for the father unless it is certain that the gift was an offering.