That is because she trusts you. Not just your judgement but you! I cared for my DGD when she was little and Marisa asked very little of me but the things that were important to her I respected. Same with the young mother down the road. Her little girl was entrusted to me when she was 7 weeks old. She knew that I would honor her requests. There were not many and like my DD, I was given free reign with her.
I believe that when you accept and treat your child's partner with love and respect you will be given that back tenfold. Good for you to share that relationship with your DDIL. everyone benefits! I hear you on the MIL from Hades but you win! I am not afraid of my wonderful husband's mother.
Oh, yes she was like waaaaaayyyy beyond the stereotypical MIL.

This is a woman who, along with her husband in their younger days, shut down a local honkey-tonk type bar because of the fight that broke out and THEY both took part in. She would fight a man, just like she would a woman. She was barely 5 ft tall and might have weight 120 soaking wet but a tough old bird. And I made the mortal mistake of marrying her golden son (she has two sons, but only one is golden

). Well, he is 53 years old now, disabled from an offshore accident and living with his Momma.
My current MIL has 6 sons, I think she is just thankful for us dils that came along and took them off her hands.

She really is a sweetheart. BUT, I have to admit that I was more mature when dh and I married, more settled and had more of a clue what marriage is all about so I have to admit to having some to do with each of the different mil relationships.
I do feel blessed that my dil trusts me with her precious children. As a brand new mom, she was open to listening to everyone's advice and experiences with their own children and then she made her own decisions. She doesn't leave lists or instructions when she leaves them with us, just the necessary items.
Someone said their mil didn't mix the formula correctly. Dil has one of those divided bowls too--really convienent. But, the first time I kept oldest dgd and they had powered formula (hospital gave them liquid) she had to tell me how to mix the stuff. I formula fed all three of my babies, but I used the liquid concentrate and a sterlizer. So I fixed a days worth of bottles at one time. When we had an infant room at the daycare, we required that all bottles be brought already prepared for the day, so didn't mix them. So, although I had lots of experience with babies, I didn't know how to mix powder formula.
The first time my mom kept one of her grandchildren with disposable diapers, she went through about three diapers before she figured it out!

My oldest are 29 and 27 and I used cloth so it was a younger grandchild and she had NEVER used disposable diapers. It was just lack of experience. But we figured it out. Now this is someone who, when she ran out of cloth diapers while keeping my son one time, made a few diapers out of my dads t-shirts. So while very capable of taking care of babies, she did have to be taught how to use a disposable diaper.
Sometimes someone's experience is just different and they really just don't know how to do something outside of that.