Splitting a Down Payment

[Paul M. DeAngelis]

Good friend of mine is looking into buying first home with about 10% down and renting a couple rooms out then paying the remainder of the mortgage/taxes etc.

They are asking if I have any interest putting in 40% of the down payment to help and as an investment. In this situation what should I ask for in return? I would think at a minimum 40% of the profits on a sale maybe 3-5 years down the road, but should I also receive some cash flow every month? If so, what would that look like.

Does anyone have experience doing this and what was your strategy?

Thank you.