In hindsight, we should have at least spelled out what we needed in the document.

"I bought some real estate" is not some magic spell that makes taxes go away, like so many like to assume.It is rather likely that the income generated by the real estate will generate a tax liability (in the current year, at least), but for the most part, the rental income has zero bearing on your W-2 income (should you have any), your interest and dividends (should you have any), your other businesses (should you have any), your non-real estate investment capital gains and losses (should you have any), and your personal deductions (should you have any). 

However they allow you to share should be pretty clearly spelled out in there.

And yes, do an addendum to the lease that spells everything out.  

I'm asking because I too agree that that should be how it works, but I'm dubious of it (especially if it isn't spelled out somewhere, or there isn't precedent [which I wouldn't think precedent could exist since we're still under eviction moratorium]).

Well, the answer for me, not that hard - the law almost spells out what you need to do.

You should spell this out in your lease.

In other words, either he pays his 2 year rate and stays or you write up a new agreement at a higher rate and he can leave when he wants.Some leases have no verbiage around lease break and others spell out contract cancellation fees.

Include how much money is being invested by your friend (downpayment and the fix & flip costs) who will be managing the project, who will be making key decisions, who is doing each segment of the renovations and spell out specifically all the costs for the flip - including: Money for renovations, taxes, insurance, and loan payments while they own the house, utilities, marketing the property for sale & the agent’s commission - if using a R.E. agent.

The more I read about partnership deals/syndication investments, this is becomes glaringly evident.As to the "outside our control" comment I had originally posted, this was not spelled out well (mainly because I didn't want to bore anyone).