Other than the age requirement and him being born in the USofA I don't see how.
I don't see how he even qualifies for the Dim debate stage. Bernie's rallies dwarf Joe's. Trump rallies dwarf Bernie's. I haven't been asked to sign a "put Joe on the ballot petition" or donate to Joe. I thought they had to get a high # of individual sigs and campaign contributions. I get asked by other Dem candidates on FB.
The guy doesn't look like he can hold up to a full out campaign much less Presidency. He's forgetful and gaffe prone. He's had at least one reported stroke. He's in his 70s and relatively thin but it's that "Old man thin."
Even if nominated Joe will be hammered with "what do you mean he better be fired by the time I get on the airplane" questions. But I'm glad he's running. It makes the Dims and their media co-conspirators look dumb.
Come the Convention the Democrats will have an "shit their pants" moment and the media won't be able to help prop him up.