Assume 5 months pass, the developer works on the product, while the other guy does only light marketing and sales (10% part time, as there is not much to go for

Assume 5 months pass, the developer works on the product, while the other guy does only light marketing and sales (10% part time, as there is not much to go for). For unexpected reasons, the non-tech guy moves to a different country, and there is no hope that the product will get sold. As there is no upfront funding, the developer's time (investment) is not compensated at all.