Charles Koch is known for his donations to right wing groups, especially climate change deniers. So had David Koch but he had been also a substantial benefactor for medical research, the arts and other estimable causes.
From Wiki:
David H. Koch Charitable Foundation
David H. Koch established the David H. Koch Charitable Foundation.[32] The David H. Koch Charitable Foundation has funded cancer research and a number of arts and science organizations, including the American Ballet Theatre, New York City Ballet, Lincoln Center for the Performing Arts, the Metropolitan Museum of Art, and the American Museum of Natural History.[1][32] An open letter to museums from 36 members of the scientific community demanded that the Smithsonian and other museums cut any ties with the Kochs, because of worries that they would remove information on climate change. The Smithsonian countered by stating both exhibits in question did examine in great detail the impacts of climate change. The Koch Foundation responded they "have pledged or contributed more than $1.2 billion dollars to educational institutions and cultural institutions, cancer research, medical centers, and to assist public policy organizations."[33]
David Koch donated $35 million in 2012 to the Smithsonian's Natural History Museum and $20 million to the American Museum of Natural History in New York City.[34] Joe Romm of ThinkProgress stated "David Koch did not personally intervene to affect the exhibit".[35] David Koch is a member of the board of trustees of the American Museum of Natural History in New York and the Smithsonian National Museum of Natural History in Washington.[33]
The David H. Koch Charitable Foundation is a significant funder of Americans for Prosperity,[36] a libertarian/conservative political advocacy group. David H. Koch chairs the board of directors of the associated AFP Foundation.[37]