You are a wonderful person and your grandchildren are lucky to have you in their lives. I say this because you NOTICED. My husband and I separated 18 months ago. The most heartbreaking thing I have ever had to do was tell our children (4 and 6) that mommy and daddy are not being nice to each other and daddy is not going to live with us anymore. We are both committed to being as involved with our children as possible so we worked out a shared parenting schedule. We need our kids and they need us. Our children are with me for 3 days and then dad 3 days. Ex-husband lives 1.25 miles from our house.
I wanted to mention the parenting schedule because it is still rough on the kids. Whenever they are with one parent, they both want to know exactly what day and time they will be with the other parent. It's as if they think we are not coming back. My daughter (4) has always been a mommy's girl, but she had a particularly rough morning today. Today is day 3 with me so even though she prefers me, she still wants/needs her dad. She woke up crying because she wanted her dad. She would only put on the dress her daddy bought her and would not let go of her piggy that dad won her from a claw machine. She was mean, uncooperative and throwing a fit for 30 minutes. Like I said, rough morning.
Before all of this, I would have described her the same as you described your "old" granddaughter. When we first separated, every morning was like this morning. My daughter's preschool teacher pulled my husband and I aside one day and said she was worried because our daughter wasn't eating at school. She did not want to play with the other kids and just wanted to color pictures of mom, dad, her and brother. To this day almost every picture she draws will say the words "mom, dad, her name and her brother's name" on it somewhere. Prior to the separation, she was the most social person I had ever meet. I used to joke that I did not know how she came from the 2 of us because we are not that outgoing.
She is slowly turning back into herself. She is beginning to make friends with anyone that will stand still long enough again. :) The rough mornings are maybe a few times a month versus every day.
You are doing the right thing by talking to her and just being there....ask her questions about if she is mad, sad, mean, etc.
My son was angry and withdrawn. He would snap at anyone if he did not like what they were saying. He is more of an introvert than his sister, but he seemed to be just shutting down. I made a point of asking him everyday if he was ok, who he was upset with and told him it was ok to not be happy sometimes. Sometimes things are just out of his control and it is going to make him unhappy. I told him mom/dad are unhappy sometimes too, but if he tells us when he is unhappy and why, we will do our best to try and help him. He was particularly angry/mean/aggressive speech towards his dad. We all sat down together and told the kids we know this is hard. It is hard for mom and dad too, but one of our jobs is to be the best parents we can be and mom and dad living together was not being the best parents we can be. We gave them a turn to tell us their thoughts and we addressed their fears/concerns, etc. We thanked them for telling us what was bothering them so we can try to help and then reminded them what behavior is acceptable and how to treat others. We told them what we expect out of them and what mom/dad are going to do to make this work the best we can. We reminded them, it is not acceptable to talk mean, hit, throw fits, be disrespectful, etc. just because they are not having a good day. Everyone has bad days sometimes, but it is not an excuse to be a punk and they will be punished at mom's and dad's house if their actions require it.
We have only had to have 2 of those conversations. Some days I will remind my son if he is not having a good day to just go take a timeout (some time to himself) in his room. Like I said he is an introvert and needs alone time. He is so much like me!
I believe us being consistent with how they are supposed to act has helped. They know they are not allowed a "free pass" to do whatever they want and they know what to expect out of us. Don't get me wrong, we all have had to bend on some rules. There is just no way my household or my ex's can run as smooth as it did when 2 parent's were on duty all of the time. We both get frustrated and stressed and end up yelling when the situation was not "that bad". I make sure I tell the kids I am sorry and mom needs a timeout to herself.
The best thing you can do is be there. Talk to her, listen to her, be honest on her level, reassure her it is ok to not be happy, reaffirm/reinforce what is acceptable and what is not, be consistent.
I am sure the situation is more difficult without their dad being close. I can't imagine trying to get my kids through this if my ex and I were not able to work with each other and be so close.
I just remembered for a while my son slept with a picture of his dad. Maybe that would help. He still has a piece of paper taped to his headboard that he wrote "I love mom and dad." It has been there for over a year now. We also let the kids pick a few things to take to the other's house that they got from/with the other parent. I know my son has a picture of me on his wall at his dad's. I am sure dad loves that!
I hope this helps. Feel free to send me a private message if you like. I have all kinds of things I could share!
I wish my kids had a grandparent like you.