Is one sinful for cutting ties with his sister who refuses to communicate with him and criticizes some rulings of Islamic Sharia?

Maintaining kinship ties is obligatory, and severing them is forbidden. Islamic law encourages a Muslim to maintain ties with his relatives even if they cut him off, and to give to them even if they withhold from him. The questioner should continue to maintain ties with his sister and advise her regarding any mistakes she makes. For this, he will receive great reward and recompense, as long as his relationship with her does not lead to harm to himself, his family, or his religion.