Ghosting is a form of passive aggressive behavior.
My experience is that this is a very difficult emotional ploy to deal with when on the receiving end. The kids and grandkids are probably freaked out
And unable to handle their emotions I don’t know what else you can do other than to let they know you miss them and so does their dad.

Hello, @boppi My name is Scott and I was my wife's caregiver during her 14+ year war with brain cancer.

I learned a ton of things as a caregiver -- one of which was as much as my wife and I might have wished it to be otherwise, we could never direct how people would react to her illness and serious mental deficiencies. Other than our two children, everyone in my family ghosted on us and everyone in her family did the same -- other than to frequently let me know what they thought I was doing wrong. We had a very close-knit group of friends of over 40 years, all of whom also ghosted on us. This certainly hurt but I also came to realize that I couldn't afford the emotional energy it took to figure out why this was true of so many people, try and change them, or wish it were different. I looked at it that this was their deficiency and was baggage they alone would have to carry in their lives.

Not much help, I know, but at least you aren't alone in this.

Strength, Courage, & Peace

This is very hard on children too. They will be going through their own stages of grief and one is anger. It might help to sit down and allow feelings to be expressed and let them know what this is like for you both and that you need their support now.
I’ve been so used to making everybody’s life better that it was hard for me to let my children know how I felt and that we need them.
I’m also letting friends know we need them.
So far everyone is ok but I do hear that as things progress and my husband is harder to be with, friends can disappear.
The ghosting is sad. I’m so sorry but hope your children come around.