That is not an easy position. However, it is important for a mother to feel like she is in charge so try to be diplomatic and take into consideration her wishes!
It's great you could help her out. No one is perfect and she may have been a bit overwhelmed. It is also great that she wants to have her parenting count. Perhaps you need to find out if she is ready to take on the responsibility now, perhaps that is what she is trying to say. Ultimately, it is her child and her responsibility. Sounds like you are a great support person for her. But set limits too. She can't have it both ways, either.