This may be a case in which the new thing has not quite kept up with the old.

If your son left few assets, you probably don't need a formal probate court proceeding in which Letters Testamentary would be issued.

So how can you collect the money? In most states, there is an informal procedure that can be used to transfer personal property of relatively small value. If it's available in your situation, you'll need to write up a simple statement, stating that you're entitled to the funds, and sign it in front of a notary. When you present this notarized statement (affidavit) to the party who has control of the funds, they'll be released to you.

You'll need to find out exactly what information to include in the affidavit, by checking your state's statute. For information on how to do that, see 8 Ways to Avoid Probate or The Executor's Guide, both by Mary Randolph, J.D. (Nolo).