Does the wife sin by washing her husband's clothes that are "isbal" (hang below the ankles), and what is the ruling on washing the underwear he wears beneath them, and what should she do if he forces her to do that?

Trailing one's garment out of arrogance is forbidden by the consensus of scholars and is considered a major sin. It is disliked by the majority of the four madhhabs if it is not done out of arrogance, while some scholars have deemed it forbidden. The advice for the husband is to shorten his garments above the ankles, out of eagerness to follow the Sunnah and to avoid controversy. This issue is a matter of ijtihad, and therefore, it should not be a cause for discord.