I wonder what Georgia's Will said. If she is like most couples, they each left their share to the surviving spouse. In this case, Bob. That would make Bob 100% in ownership of all the marital properties and funds. So if Bob remarried, added his new wife to his accounts, and to his Will, he may have done the same thing, left all of it to Fontelle, therefore leaving the 3 daughters out of it. Now Fontelle is in control of it if she survived Bob and everything goes to her children, effectively leaving Bob's children out of it. I can see how this would sit sideways with them, thinking their mother's half was going to this woman, as well as them potentially ending up with nothing if Bob didn't provide for them in his Will. It could be as Bob went along the way, buying houses and giving money to his daughters and grandson, that he felt he'd given them quite enough.
So it would be imparative to make sure that Bob didn't get the chance to do that. He had to go, he had to be gone, he had to disappear in order for them to protect their interest in the estate.