Mean Daughter-in-law

I would let it go at the moment, you can be the bigger person and treat both children equally, don't let her attitude mar your relationship with them.
If things escalate you may have to talk to your son but for now bite your tongue.

Please let it lie. My DIL fell out with me over a concern i expressed and the punishment is more or less total estrangement from my son-he is piggy in the middle- and i have only seen my youngest GD three times in the past year and my elder two not at all.It just isnt worth the heart break. Hold your tongue and bite your lip and carry on regardless is my advise.

I am in agreement with baggs here. You continue to behave like a sensible adult. Pay as little attention as you can to unkind texts and love your grandchildren equally & demonstrate that love as you know is right. Do not give oxygen to DiLs behaviour., it would only increase!

I think you're right to treat them equally. Your DIL is in the wrong. If she persists with nasty texts, maybe speak to your son but perhaps not just yet.

Thank you so much for your input.

Let it lie. She's not going to change at that age. Carry on doing what you know is right and giving the same love to each of the children.