I'm glad that it seems like he's extended the longevity of his life by losing a lot of weight. Have you seen him now? Looks amazing for his age. I think if he continued where he was, he might've passed away at some point or be in a worse condition.

He needs as much time as possible to decide what he's going to do after he's gone.

Safest option would be to turn Valve into a foundation, similar to Zeiss: The company owns itself thus can't be bought out, statutory stipulations go along the lines of "Make sure we don't go bankrupt, do great optics, funnel some money to the University of Jena as well as less well off workers in the city". No grand charitable aspirations besides being a good citizen as per 1846 bourgeois values (though that'd be Gabe's choice), otherwise just continue as they've been doing. Make sure all stakeholders (incl. gamers, or at least Valve customers) have standing to enforce those statutes.