When i was DF, there was 3 people that came to visit me one by one. They broke the rules to do so. By doing that they showed me respect and that they were not in agreement with the judgment. Those people showed by their actions that they were indeed real friends. Friends that were prepared to break the rules.
I had discussed with them all the reasons the Truth was wrong, and they agreed. not one of them is in the truth now!.They too took a stand when able to do so.
My point is that you NEVER know her real reason for sending you that soup!. Don't presume that she has bad intentions, Your DF may have awoken a cord inside her. Simply make the chance to talk to her and say, name,, thanks for the soup, you are breaking the rules to send it to me? why?. you may be surprised and get a chance to counter witness the real truth to her as i got. and even to others. if she did it to patronise you then give her the message!, but otherwise take the chance given to you!.
Remember that yes she may have shunned her daughter, but many things can trigger a wake up, she may respect you greatly, Let her know the real truth.