Heartbreaking parenting style

I don't think you can Jocando. All you can do is be yourself and whenever you have the opportunity, you can share your wisdom with your DGD.

Trust your DD. After all you reared her so have faith that all will be well.

I don t mean this to be rude Granaretto but the fact that Jocando raised her daughter in hopefully the best way, doesn’t mean that outside influences, haven't negated that presumed good upbringing.
I too would be very worried if I had a child who was bringing up a grandchild in a harsh or uncaring way
Harsh words/phrasing is a form of child abuse Tha child will either pull away with very low self esteem or become a bully herself.
All you can do at this stage Jocando is give the little girl very positive messages and feedback when she is in your care
(which I hope is often)
Is there a Dad ?

I completely understand your distress but however carefully you word your advice I think it will be received as criticism and may even make things worse.

When your gd is with you, you can give her the positive messages that she needs and I can tell you from experience that this does help a great deal.

In the meantime is your dd having difficulties? Does she need support?

In my opinion, with this sort of thing unfortunately, is to pray to God.
If you are not religious, then ask a Christian you trust, to put your GD and family, on their prayer list.

There then may not be an immediate change, but hopefully things will change for the better.

Giving unsolicited advice is never a success.
All you can do is to model a different way of speaking to your DGD when you interact with her.
This must be difficult for you to hear.

I can imagine how you feel, but as others have said giving well intentioned advice, no matter how important you think it is, can result in a worse situation, even a complete withdrawal of access to your GD.
Just be there as much as possible for your GD, and your DD of course, who could be struggling. Suggest looking g after your GD more to give your DD a break, and look at children’s books for your GDs age that you can read with her, that encourage positivity and expressing emotions. There are plenty.
Wishing you all the best with this.
💐💐