What is the ruling on a grandson preventing his wife from visiting her maternal and paternal uncles, and on one of the maternal uncles cutting off his visits to him and depriving his wife and daughters of him because of this?

The husband's brother (or his relative) is like a stranger, and their entry upon women poses a great danger. They are more deserving of being prevented than a stranger due to the ease with which they can be alone with the woman. The husband's paternal uncles and maternal uncles are not relatives of the wife whose kinship ties must be maintained merely by virtue of this relationship. There is no sin upon the husband if he prevents his wife from sitting with his paternal uncles and maternal uncles, nor is this considered a severance of kinship ties. If the husband fears for his wife temptation or falling into something unlawful, he must prevent her, as he is responsible for her honor. The maternal uncle should not abandon the husband for this reason, as the husband has not committed anything unlawful nor has he neglected a duty.