I had bonds growing up that were both in my name and my grandfather’s name. He had ownership over them. I don’t know that I could do anything about it if he didn’t hand them over. I would think they would be a shared asset between the parties named on it. The answer should be easy to find though if you google it.
As far as the life insurance, if your son was still named you should have heard something. I suspect that he was dropped from that policy before the grandfather died.
My question to you really is why does it matter? The man signed his rights over 8 years ago. I understand you want to get what you think your son is entitled to but those ties have been severed. Do you really want to drag this up and possibly open old wounds? My daughter’s father signed over is rights as well about 10 years ago now. I honestly don’t think I would even want anything that family had to offer but I can tell you without a DOUBT my daughter definately wouldn’t.