On this website, I do not always get to give good news, and this is one of these times. I understand that hearing things less than optimal is not easy, and I empathize. Thanks in advance for not "shooting the messenger."
I am afraid that there is no way to force them off without going to Court. However, someone in your situation can file for what is known as a PARTITION in Court, asking the Court to decide what to do with a titled asset when the owners cannot agree. If so, the Court decides that it should be sold and proceeds split, or, one party should buy the other out in lump sum or payments, or whatever else the Judge feels is equitable.
Perhaps the threat of doing this (litigation is time consuming and expensive) would be enough to have him agree to something that is amicable for both.
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