This needs the review/retention of a real estate and estate planning lawyer, who will willingly review it for no charge (30 minutes), but then...

A free review by a licensed Michigan atty will give you the assurance you look for. Any should step up to do this.

Other than what Ms. Fanning advises, you either buy it or a new one. As a tenant only, you have no rights.

There is no guarantee they WILL live there until dying!!!!

Not likely. Your vagueness needs a better articulation of facts and motives on your part. What is the purpose of this “configuration” you have...

What did they invest inY YOU after you entered into the agreement? Did you agree to a minimum employment period?

You NEED to retain an attorney now. There are title transfer issues to address in addition to the amount owed. This isn’t like buying from a...

Was there a second name on the bank account? That seems to be the only way the money can be missing now? Not all facts are clear here.

No. Likely only a money judgment for what is due you. For an order to repossess the horse, you needed to file a claim and delivery action. ...

File an action in the circuit court where you reside against cousin and any other interested parties. Hire an attorney and accountant to fight this.