How long will an insurance company search for a missing heir

My former father-in-law passed away 1 yr. ago. He left a life insurance policy to his children, one being my missing Ex. I have spoken to the insurance company and they advised that if he can't be found my family would get my Ex's benefit; then they come back and say my family would be entitled to 50% of his benefit. They are running a search for him. How long will they search for him?