If your W told you that it was up to you, that she didn't want to tell you that you couldn't go, then take her at her word. Go for yourself only if it is meaningful for YOU to say goodbye to her grandmother in that fashion at that time. Otherwise, don't go.
If you would like to go in order to comfort your wife and your inlaws, but you know that it won't happen like that, then don't go.
Don't let it be about your in-laws or your wife or what anyone else thinks of you.
