This is a more complex question than you think. In general, and without expressing an absolute answer, if he doesn't agree to sign over to you, whether for free or for payment of some amount of money, then your only other option is a lawsuit for what is called partition to divide property and determine the amount you would have to pay him to make him give up interest in the land.
Answered on Apr 16th, 2013 at 10:36 AM