I was sort-of in similar situation. Though I recognized I'm only an employee for simple reason - I was paid for what I was doing. In the same time founder of the company would not pay himself if there was a bad month (it's another story that when I was joining him I was told there is 1 million on the bank account...)
Are you paid monthly salary or do you contribute your time as investment (i.e. living on your savings)?
Also - this key executive - what does he bring to the company? Contacts? Money? Both?