We own land. Should we partner with builder?

[Brian Christensen]

My parents own about .8 acre on Main Street in our town expensive/expanding town. Hot market. Homes gone in a day with cash offers. They have an old building there and we were considering tear down and building townhomes. I contacted a builder who is building townhomes across the street. We will meet with him today. My parents own th property outright. They want to partner with the builder, where they have the property and the builder brings the construction. What terms will the builder be amenable to and how can we profit from a deal like this? Would it be just as profitable to sell their building/land and not build? I understand that their are unaccounted for variables. Thanks for your expertise. 
Brian