(AP ) Lucas is currently the chairman of Edutopia, which is part of the George Lucas Educational Foundation. He could put money into that or create a new foundation which would be funded from the sale.
George Lucas Donating Disney Sale Billions to Charity
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NOVEMBER 02, 2012
Alex Ben Block, The Hollywood Reporter

By the end of the year, the $4.05 billion sale of Lucasfilm to Disney should be finalized. And since George Lucas owns 100 percent of his company - which has little to no debt -- all that money goes to him. “George Lucas has expressed his intention, in the event the deal closes, to donate the majority of the proceeds to his philanthropic endeavors.”