If you are looking at a start-up trajectory, plan to take on additional money, etc, treat his money like a third party investment and value it separately from h

If you are looking at a start-up trajectory, plan to take on additional money, etc, treat his money like a third party investment and value it separately from his role (and equity) as a co-founder. To properly do this, you'll have to come up with a reasonable valuation for your company. It should be somewhere between 100k and 200k if you are starting from zero. If you are looking to bootstrap, then treat the money like a loan.