Need help on first CMR development and how to structure equity deal

My father has a property (.96 acres) where he wants to build a condominium unit (35 units). I have been helping him get things together as best as possible and we have started construction documents and pre-construction with our chosen CM. Property is worth about 3-3.5M. We are estimating construction costs come in around 13.2M. We are seeking 14M from a primary lender and have received lots of interest in the project. Unfortunately my father does not have much liquidity so the bank is recommending we either raise some cash from liquidity partners (friends and family) or bring on an equity partner so we can get this loan finalized.

This is where we are starting to enter uncharted territory, at least for my abilities and knowledge. I am looking for recommendation on the best way to structure a fair deal for both an equity partner and ourselves. We have an investor interested but they mentioned they don't normally do deals under 30% IRR. I think they could be interested in the 20% range though, based on conversations.

Any thoughts on how I should structure something?

Build is 14 months, sellout is 17 months from construction start. Gross revenue should be around ~7M.