Hi. Please be patient while I provide a bit of background so you can appreciate the position I'm in.

I inherited a 6.8 acre junk yard in New England when my dad passed in Oct. 2017. We had to close down the recycling business because of settlements with various environmental agencies. We then rented the entire property to a trucking company who was subletting to other trucking companies. The rent was pretty good ($25,000/mo.) but these trucking guys were changing oil outside and causing more environment concerns than the junk yard did. I didn't take long for the city to sue me and them together, forcing me to evict them. During their cleanup process the city raided the yard accusing them (and me by extension) of illegally burying metals and oil, forcing me to pay for a fire detail for the next 2 months, costing me about $35,000.

So, I haven't received rent since April 2018, I had to remortgage my dad's house to pay for the fire detail, back property taxes, legal, fees, LSP fees, etc.

Now, here's my question: Luckily my property is zoned for marijuana cultivation and I was approached by a company that wants to cultivate on my property. There is an old 5,000 sf building on the property. They want to use the existing building to get their foot in the door and then build a 20,000 sf building next to it and make 10 times the revenue in years 2-n. When they told me their budget for rent was $4 - 7 K for that size building I told them I'd be tying up all my land for this business and I was getting $25,000 from the previous tenants. I asked about entering into a joint venture and they offered me 10% of the net income.

I have 2 dilemmas:

1. They may not make much money in the first year growing in the small building, but I have to keep paying the mortgage on my dad's house, pay more back taxes, pay the LSP to completely close out the environment case, the attorneys fees, etc. I asked him for a minimum monthly rent because 10% of 0 is 0. He is currently balking saying I could take the equity percent or receive flat rent.
2. He is expected me to put up the 20,000 sf building at the end of year 1. He said I should pay for it because it is on my property but my attorney (who writes lots of commercial leases) says it's unheard of for the landlord to pay for a new building, even if it is on his property.

There could be tremendous upside to having a 10% stake in this kind of business, but I'd like to ask your opinion to see if I can come up with an idea that would be a win/win for both of us. Should I use my 10% equity payments to fund the new building, which a quick search leads me to believe could cost more than $500,000 just for the shell, so that this cultivator can use it for the next 5 to 10 years and keep 90% of the new profit. Or should I ask him to pay for it and then I could possibly pay something for the building when this joint venture is over assuming the building has any value to me on my property?

Any and all ideas/opinions are welcome.  Thanks!