It's his job to figure out how he can help. He's supposed be a self-starting entrepreneurial animal right? There's absolutely always something that can be done

It's his job to figure out how he can help. He's supposed be a self-starting entrepreneurial animal right? There's absolutely always something that can be done. Even if it only moves you forward 0.01% it's still worth doing. Even if he needs to learn a new skill so he can help more that's what he should be doing. That said, it can be hard. The early days are usually very tech heavy. It's not reasonable to expect that he's really creating 50% of the value right now. But he can put in a roughly equal amount of effort.