Can a person be held to an oral promise?

Oral contracts for the sale of goods for more than $500 must be in writing or they are not enforceable. However, this rule will not apply if there is substantial performance by both parties reflecting the terms of the agreement.   In this case, the car is a good and is therefore, subject to this rule.  the fact that the parties performed their respective obligations under the agreement demonstrates that the parties wanted to be bound by the terms of their agreement.  Becasue the son paid mom back for the car, she is obligated to now sign the title over to him once he gets insurance.  if she fails to turn over the car, he may sue her to recoup his money as she breached the contract.  I would however, try to resolve this without litigation as no judge wants to hear a family dispute like this.