It doesn't work that way. Whatever his stated intentions were, the insurance company will divide the money however he specified on his last beneficiary declaration. IN other words, he might have changed his mind from what he said, or he might have named ONE person with the hope that they would share, but they have NO OBLIGATION to share.
The claim gets filed. The insurance company pays the beneficiaries directly. The payment will be made, in normal circumstances, about three weeks after ALL the paperwork is filed.
To find out, you need to go through his personal papers, to see if there's a copy of the policy. You need to go through his cancelled checks for the past year or two, to see which insurance company he paid. Then you can try to call them, but if you're not the executor of the estate, they likely won't TELL you anything - as it's private information.
There is no "central database". Social security is totally unrelated to it. And insurance transactions are private, so there's no "third party" you can go to to have them research it for you. It's ONLY going to be about his peronsal papers.
agent, 21+ years