How to Invest our money to help a buyer flip home

[Kathy Evert]

We are new to real estate investing with 1 property.  We have an aquaintance who buys and flips homes.  They had a hard money lender who made a commitment using 401K's and due to changes in their employment they no longer can do that.  We could invest to help but are not sure what is the best way to do this.  If we lend $100K what would the interest be, what contracts needed, what percentage on the back end sale should we expect.  It's a 2 month flip.  We know the people as they did work for us in the past.  Any advice appreciated.  

Kathy