The mother of Grandchildren has Broken Court Orders For shared Parenting and Access to his Children

Oh my...touchy one. To whom would to send the text? If it is to the older child, I would perhaps say thank you and we really enjoyed the gift and leave it at that. You could also send the same text to the mother, but no mention of anything else. You do not want any animosity at this time.

This is quite routine, parents who have custody have 101 reasons why children cannot visit the estranged parent, it causes a lot of frustration. If it gets to the court the result will be a slap on the wrist and attitudes will harden on both sides, with accusations of neglect and abuse made.

As a Grandparent stay out of the squabbles, sends greeting and presents as normal, dont rock the boat.

I agree with David0205, you see this for your sons POV but you have no idea whether the mum had good reasons or not for not adhering to the contact plan. Stay out of it and the distance will give you the best chance of maintaining a relationship with your grandchildren whatever the outcome at court.

Presumably if the mother had had "good reasons" for not adhering to the contact plan she'd have made the father aware. If she didn't have good reasons she shouldn't have gone against the arrangement.

What babyshark said

Why did they get divorced? Is it a high conflict divorce?

Wether the Mother had good reasons or not, leave the couple to sort out their own differences, very often there is just not enough cash to pay for 2 households and the mother cannot manage, added to the emotional upset just makes the rift worse.

You say you were given presents from the children, did they come via the mum or their father. Yes, of course, text/message or send a card thanking them for their gift and saying you hope they had a good Christmas.