For those that didn't listen to the podcast, a few notable (and eye-opening) take-aways, including some google gems.
1. The escheatment rules vary not only by state, but by account type & institution. In the case of the OP's friend, it seems a letter was sent, but this isn't always required. Colorado & Indiana, for example, consider an email in lieu of a 1st class letter to be sufficient "due diligence". Hope it didn't end up in your spam folder.
2. The system, which is supposed to protect the little guy, has now turned into another revenue stream for state coffers. Unsurprisingly, dormancy periods have been reduced and there's a push to eliminate the physical letter requirement, citing the increase in postage stamps as justification. (I kid you not). And in the case of searching for unclaimed property, the state databases are intentionally not-linked, despite using the same software and web interface. You have to search each one individually.
3. There's a 'death index' which is exactly what it sounds like. It seems reasonable to me that a dormant account about to be transferred as "unclaimed" should be compared against the database of the deceased, yet that's not a requirement.
4. It's not just investment accounts, it's bank accounts, checking accounts, and safe deposit boxes that fall under these rules, too. If it's under $50 in value, you are not required to be notified when the contents are taken.