Children need empathy along with the limits of their parents, and what you react to with your stepdaughter is that this balance doesn't seem to be banged. With your account, your stepdaughter will not tolerate any discomfort for your daughter. She needs to experience her to develop the world's resilience and capabilities. Maybe this is because of the way your stepdaughter became a parent, and she is trying to emulate or leave it.
Sometimes they fear single parents are “bad” when navigating divorces or making up for the pain from divorce by “protecting” their children with extra kindness. Or maybe your stepdaughter feels that adopting his parenting style is one of the few ways he can maintain a sense of control while dealing with uncooperative extremities.
In families with increasing numbers of adults in their homes, children benefit from seeing how to handle different situations and do not live with their granddaughter, but you are one of the adults in her life. You can adopt an aquarium approach and she can express her emotions without your light emptying (she is not a “bad” and struggles with emotional regulation). (We're trying to have dinner so we can't eat cookies now, but we can get them later.) If your granddaughter responds, you don't need to respond, you can redirect her by inviting her to play the game with you instead, and if she continues to refuse this, it's still warm and unreactive.
The more comfortable your granddaughter feels with you, the longer it takes without a mother. (As a single mother, your stepdaughter may enjoy downtime!) You may be surprised at how your child can adapt to different expectations in different environments when those expectations are provided with warmth and consistency.
You can also work to strengthen your relationship with your stepdaughter by not making a difference. When she feels she is seen and appreciated by you, she may become interested in parenting like you are modeling. However, even if you don't adjust the tendencies she describes, if her daughter witnesses a friendly, contested relationship between your two, this girl will tend to trust you and try to embrace your approach more. And when you feel the surge in frustration from looking at your stepdaughter's parents, pause and ask yourself what beliefs and experiences are informing you of your reactions. This self-awareness helps to engage more constructively with both stepdaughters and granddaughters.
Ultimately, you can't control how your stepdaughter raises your daughter, but you can control how it shows up in the dynamics of your family. You may need to reconcile your expectations and realize that if you can position yourself as an ally rather than as a critic, your impact will be at its peak.
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