Can't find the lawyer, start with the first child listed in the obit, that's usually going to be the executor, and ask if any estate was opened (ie, a lawyer). No estate, talk to the heir directly.
Companies, even oob companies would still likely have a Registered Agent in their respective state database.
Or you could turn over the whole thing to an estate lawyer who has their head screwed on straight.
Usually to enter an Unclaimed Fund in any respective state Unclaimed Fund database requires a FEIN to submit via NAUPA reporting. Here is a directory of each US state's reporting rules.
Yet most states do have a miscellaneous option -- for instance NY provides a "Other Miscellaneous Property" entry on their verification form to submit Unclaimed Property.