My father ‘deliberately and hurtfully’ cut my late sister’s two kids out of his will. How can I ensure they get their fair share?

https://www.marketwatch.com/story/my-father-deliberately-and-hurtfully-cut-my-late-sisters-two-kids-out-of-his-will-how-can-i-ensure-they-get-their-fair-share-32d5ddc5?mod=mw_rss_topstories
“How can I best do this in such a way that nobody is penalized from gift taxes and other costs?”…