Sorry to hear about your problem. There is nothing worse than family disagreements. Frankly if your fiance does not have any written agreement that says the truck is his at some point in time this dispute is just his word against his father's. If he and his father can not agree on a resolution, your finance is left to sue for one-half the then fair market value of the truck once the loan is fully paid. It may be that this amount is within the small claims court's limits (currently $5,000 in Connecticut).
Of course at that point it is your fiance's version versus his father's version and you have not way to know how the magistrate will rule.
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