How can I maintain kinship ties with my maternal uncle, who works in selling cigarettes and shisha, given the impermissibility of consuming from his money?

Selling tobacco is forbidden (haram). If the maternal uncle has no other wealth, then it is not permissible to eat from his wealth. If his lawful (halal) wealth is mixed with unlawful (haram) wealth, then it is permissible to eat from it, though it is disliked (makrooh). The questioner should advise his maternal uncle with wisdom and gentleness, for "religion is advice," and "whoever sees an evil, let him change it." If he advises him and does not eat from his unlawful wealth, this does not mean severing family ties. Rather, he should maintain the relationship as much as possible.