RALPH: Yes. I have provided for myself. I have a substantial portfolio. It's critical that I check on it. Let the bank know that I am alive and well.
PICARD: Your lawyer has been dead for centuries.
RALPH: Yes, of course I know that, but he was a full partner in a very important firm. Rest assured, that firm is still operating.
We don't merely talk about deposits or money market products, the guy also held shares and bonds and believes that they they are still worth something just like he believes that the company of his lawyer still exists.
The average lifespan of small companies is probably a few years whereas the average lifespan of publicly owned and traded companies is probably a few decades. Any stocks or bonds you hold become worthless once the company ceases to exist.
About belief, you are the one who actually believes that the guy is a "seasoned financier" (nobody who ever had something remotely do to with finance would naively believe that all people in this business are competent, not to mention that using such a phrase after the financial crisis makes you sound even more naive). I don't believe anything, I judge him based on his actions and words. They reveal that he can either not accept the reality or that he is incompetent. Sorry to shutter your lovely little world but guess what, people with some power or money are actually quite often utterly incompetent.