Is the husband's mother entitled to invite her daughter and her husband daily and bring visitors into the couple's home in their absence, and is the wife sinful if she speaks to her about this?

The basic principle is that no one is allowed to enter another's house except with their permission, and the one who grants permission is the husband. If the husband agrees to someone entering in his absence, there is no harm, as long as entering the bedroom does not result in harm or offense to the wife. If the furniture belongs to the wife, her permission is required for its use. It is a good quality for the wife to treat her husband's family well, while retaining her right to prevent harm to herself, her belongings, and her privacy.