One reason I inquired about the protagonist is because the Latino movie audience is big in the U.S., getting bigger, but there has been a paucity of mainstream films targeted to that audience. It seems to me that this is a movie that would appeal to that audience (as well as the Latin America market)...
...But to do that I suggest you consider enhancing the role of the gardener. Either
1) make the gardener the protagonist.
2) Or make the tycoon and the gardener co-protagonists. The standard rule is that a story should have one protagonist, but there are exceptions to every rule. Some artistically and commercially successful films have had co-protagonists. Two that come to mind are "The Odd Couple" and "Butch Cassidy & the Sundance Kid" which only happen to be written by 2 acknowledged masters of the craft, Niel Simon and William Goldman.
3) Stir the plot by either making the swindled tycoon female or having the male tycoon move in with his former Mexican housekeeper. Romantic complications ensue as they struggle to regain the swindled fortune.
Again, they could be co-protagonists which is implicit in many romantic films. See "When Harry Met Sally", "You've Got Mail", "Pretty Woman","Moonstruck", "The African Queen" and "Adam's Rib", "Bringing Up Baby" -- to name a few.
Whatever, I think your basic concept is very, very marketable. ?Buena Suerte!