I'm reading the Broadview literary edition. It doesn't make the correction Cheryl's text notes and sticks with 'she was wearing black ribbons for his wife.'

This edition makes the following note:

wearing black ribbons for his wife:The various protocols of mourning were strictly defined at this time. Even though Sir Walter and his daughters have not seen Mr. Elliot for years, and his relationship to them is not close, they must make some show of public mourning for the death of his wife.

The note goes on to observe that there could be dire consequences in family relationships and connections if one failed to observe the mourning protocol, which included other customs and observances other than the black ribbons.