He does not advocate "open borders". He does humanitarian aid for refugees. In Europe, he supports many pro-European groups. That means open borders by extensio

He does not advocate "open borders". He does humanitarian aid for refugees. In Europe, he supports many pro-European groups. That means open borders by extension, because the EU has abolished borders. But it's not a specific goal of his to increase migration. The "Open" in "Open Society Foundation" also has nothing to do with "Open Borders". A open society is defined by freedom of speech, equality before the law, high social mobility, more interested in trying new ideas than in defending the status quo, etc. It's the same ideology that made him spend his first billion on fighting the communists in the 1980.