Not if there are social, political, and ecological costs to other people.

What makes you think that "free" should only ever benefit you, and everyone else's "free" is irrelevant?

Very few things don't have a social, political, or ecological cost to others. How that money was earned to being with, purchasing choices, etc.

Taking away that money also has such costs.

> ...free people, living in a free country, should be free to give their wealth to whomever they please, including their children.

Sure. And those children should be as free as anyone else to pay the appropriate tax rate on that category of income. (Given that it's a sudden unearned windfall, a pretty high rate seems quite equitable.)