Friend lost his wife last year. They filed Joint Return. Their joint bank account got $2,400, just like ours did. I can't find the link now, but there is a link about this issue. Basically, it's like a S.S. check after someone dies. No one gets to keep it, ultimately. This is apparently fairly common. It's amazing that the government sent checks out without vetting recipients. In 5 minutes, I can devise a system to do that, but they just started mailing us all our welfare checks willy nilly. But I don't think "the IRS is just letting them keep it" is a valid statement.
However, chaos reigns, and what is really going to happen is up in the air. I know my mother and crazy brother haven't seen a nickel yet.