If he trusts his tech, as clearly he does, and needs funds now I don't see the harm. After all it really comes down to whether he succeeds long time and not whether he keeps all his coins just to satisgy current market needs.
At 7.75 and falling, he probably saw the writing on the wall and got out while the getting is good. Any remaining ETH he holds is pure speculative at this point, and I dare say a big mistake as the whole project is set up to decrease in value. Zero cap on production, units valued by computing per/unit, which as we know is a huge downward pressure on pricing. CPU cycles are getting cheaper every year, not more expensive.
But anyone with basic logic can suss this out, what amazes me is the absolute HOPIUM surrounding the project itself. Nobody has a pressing need for decentralized computing at this point, and there are plenty of free open source alternatives and commercial providers to choose from.
Its been dead in the water since its inception, and they're just gradually realizing this.