Is there sin upon one who shuns his sister who incites their mother against him, knowing that the sister does so out of greed for money?

Filial piety is one of the greatest duties. It is advised to maintain filial piety, uphold ties of kinship, and overlook the misdeeds of relatives, based on what Muslim narrated: "If what you say is true, then you are feeding them hot ashes, and you will continue to have a supporter from Allah against them as long as you persist in that." And due to the saying of the Prophet, peace and blessings be upon him: "The one who maintains ties of kinship is not the one who reciprocates, but the one who maintains ties of kinship is he who, when his relatives cut him off, he connects with them." Some relatives can be guided and advised.