@rbynaker  I'm sorry for taking offense. I misinterpreted your comment.   This situation has me crazy.   

I think the father was looking after his financial interest and the attorney came up with this.  With the way land prices keep going up in this area, I think the father wants to be able to share in the profits if the son decides he doesn't want the farmers life in the future and they decide to sell.  If he'd just sold out right, he would miss out.