Sounds like she has a narcissistic streak in her.
She may know your weakness and knows how much you care and knows that if you feel sad then that’s an opportunity for her to get something from you. If you don’t do what she wants then she plays on your emotions for the grandbaby and her. Don’t keep giving in to her she will need you before you know it.
they're selfish, manipulative, immature, and hold some form of resentment...women are far worse than men at holding grudges...
You'd have to provide a lot more details. I had a daughter who used her children at weapons to hurt me, and I knew each time, why she did it. I had to wait her out each time, until she was ready to let me in again.