I wish we had the answers to some of your questions, but the great mystery is that we cannot answer a single one, despite hundreds of attempts. Our best guess is that he was named George Brody, that he was sometimes called Bobby, that he was born around 1905 somewhere "back east" in the United States, and that he probably lived in the San Francisco Bay Area from at least the 1940s. It's really a needle in a haystack, and it might not even be worth your time to look at the library records, considering how little we have been able to find from newspapers, census reports, genealogy sites, birth records, passports, etc. It is very good of you to offer to do this, however.
I have to respectfully disagree. I think there exists far more information on paper in libraries than what is available online. I think the internet only offers a fraction of what can be traced via a library which would have local info. When I searched my families history in Will County at the Joliet library, none of what I found there was availabe online. I'm not even sure the smaller local newspapers would be available online.. I know of several in my area which are not.
We've traced the GB from the voter registrations and online article back to 1936 as they have the same street address. I would start with 1936-1941 and work backwards given whatever info can be found in the Oakland area... and possibly with that L middle initial which Annasmom found on a letter in the BFH.
As for the name Bobby, Margaret called him that while hospitalized correct? Was there anything noted she did so before she had the brain cancer? It's possible that, with a brain tumor, she may not even been fully aware of who he was at the time and started calling him Bobby. A tumor/cancer of the brain may have started playing tricks on her mind.
jmho.... respectfully.
Cubby