Investing on a refinance

[Elias Ordenana]

Hello all , I'm not sure if I posted in the right area. But I'm looking to invest. I have a partner that needs to refi their investments rental which they owe approx 90k. They are in a ARM loan which now they are in negative cash flow. They cannot refinance into a fix rate 15/30 yr because income is to low. If we can uptain a new loan under both of our names how should we split profits on: Rental income? Percentage when property is sold? Or anything idea so we can both come out winning from this. Or am I even entitled to anything? You thoughts ? Thank you