Is a person sinful for refraining from visiting a neighbor who smokes shisha, and for refusing to allow his wife to sit with the neighbor's wife due to the smoke pervading their house, knowing the harms of passive smoking?

You must avoid your neighbor when he commits a sin, so that your heart does not become accustomed to seeing it and remaining silent about it. If you are compelled to sit with him during that time, you must rebuke him in a good manner. Abandoning a neighbor during a sin does not mean neglecting his rights; rather, his rights and the rights of neighborliness must be fulfilled at times other than those, and among his greatest rights is guiding him to good and warning him against evil. As for the wife, her ruling is like yours: if the neighbor's wife commits a sin, do not sit with her. Otherwise, there is no objection to visiting her, while avoiding times when something harmful is present, such as passive smoking.