A gift for brother's wife out of obligation???

by Wanting to gift a DIVORCE
(USA)

Do I HAVE to buy my brother's wife an individual Christmas gift?
We are sending them a fruit gift box & have also purchased him a gift certificate to a favorite place. Do we also HAVE to buy her something else?

This woman has been terrible to our family. She books plans after we invite them to events (our kid's birthdays, parent's birthdays/anniversary). She plans parties for his birthday etc and never extends an invitation to anyone in his family. We realize the choice to attend or not is his to make, but he chose her as a wife...none of us did!

In the past we, my family & our parents, have gone out of our way to purchase items we know she likes. She never thanks us for the gifts nor mentions them if we see her in person (rarely - thankfully!). Despite this behavior we have continued to purchase gifts for her. This year, I am just not feeling like we should be so thoughtful. To avoid hurting my brother we chose to send the gift box to both of them. Is this enough? I felt this was the best way to handle it, but need some guidance from someone outside the situation.