Is the husband sinful for preventing his wife from [seeing] her sister if the sister gifted the wife cigarettes that the wife concealed from her husband, and is there any doubt in accepting the gift?

Smoking is forbidden because it is among the impure things, and due to the religious, health, social, and economic harms that result from it. Harm must be repelled.

It is not permissible to accept a forbidden gift like cigarettes, and "Indeed, He who forbade its drinking, also forbade its selling."

The wife should have advised her sister gently and kindly, because "Religion is advice."

It is not permissible to be courteous in accepting what is forbidden. One could have politely declined the gift.

It is not permissible to prevent the wife from visiting her sister to maintain ties of kinship, unless one fears corruption for her from that visit. In such a case, she may be prevented from the aspect that could cause her corruption, while allowing her to maintain kinship ties through other means, such as phone calls.