Equity: If he had not helped you, would you have started? Or got as far as you have? Does he want equity? If he is happy with a lump sum settlement, then pay h

Equity: If he had not helped you, would you have started? Or got as far as you have? Does he want equity? If he is happy with a lump sum settlement, then pay him what you both think is acceptable for what was achieved/developed up to the point he left. Advisor Role: Good idea to save you money in the short term and get external and experienced eyes looking at the code/work. But, if he is not interested in the long-term will he provide valuable and considered advice? Are you making things worse for yourself trying to keep him onboard? Personally, I'd say it is probably wise to part ways and employ him on a consultancy basis to help you as and when needed. It keeps things cleaner and less complex.