Don't listen to a word he says about how things will be split. Neither his wishes, nor yours, are going to count for much. It is going to come down to state guidelines, get to a lawyer, and find out. You might even be able to find out a lot in a free consulation.
As far as his family goes, well, they are his family first, and you are probably not going to change what they think. Though I wouldn't be shocked if you find more sympathythan you expect. But don't fish for it. You should make sure that you absolutely know in your heart whether you really want to expose him to them, or not. It might feel good in the near term, but in the long run, I'm not so sure. In five years it won't matter to you, but you might do damage that can't be undone. Not that he doesn't deserve it, you just need to decide how you feel about that.
