Why is LG not entitled to all of RG's estate?
I would think that LG would be entitled to all of anything she held jointly with her dad. Beyond that, it would depend on any wills/trusts/etc. that RG might have had. My understanding is that he did not have any of these plans in place, nor did he have a wife or other children. Is that correct? If so, I would say LG is entitled to all of RG's estate.
I don't know what the intestate rules are in PA. If this had happened in CA and the situation was as described as above - then yes, LG would get everything as RG's only heir.
And of course that doesn't consider any complications that might arise because of RG's missing status. But once the Court declared him deceased, LG would take the estate.
Salem