YTA. “Short sighted”??? Your ex husband wants your kids to spend some time with the man who raised him, who he probably loves so much he wants to show off his kids to, to have some last fun and imperfect memories with his children and his father. - this is about more than your kids seeing their grandpa. It will help your husband through this extremely difficult time.

Please try to see the situation outside of whatever struggle or resentment you hold towards your ex. Your kids missing a week of school to spend some time understanding where they came from, to hear the stories of their family that will be brought up joyfully at this time and maybe never again. They may have some hard questions surrounding death, but there really is a slim chance that the grandpa will just die in front of them - this is an excuse and a poor one at that. It might be hard but if you explain to them that they need to be there for their dad it is a great lesson of compassion to see you put aside your differences.

You are being short sighted here and I hope that you see that. Not trying to be rude at all. In my opinion you should reconsider.