Is a wife considered sinful if she prevents her husband from giving his financially well-off parents a portion of the provisions or food he buys, even though they also receive assistance from the wives of their other sons?

If a husband provides for his wife and children in a reasonable manner, then there is no blame upon him for spending on his parents, even if they are not in need, and the wife has no right to object. However, if the husband brings his parents things that exceed their needs to the extent that they do not benefit from them, then it is permissible to alert him and advise him to bring them what they can benefit from, and not to spend his money on what they do not need.