Let us be clear here. All he is really doing is avoiding income and estate taxes. His family still controls the assets, but holding them as a non-profit shields the money from future taxation.
So what we have is a billionaire "not paying his fair share," but of course no one on the left will complain in this particular case because, you know, climate change. In fact, he will be hailed as a saint. This is the Bill Gates strategy of asset management.