I'd take him very seriously if he was ordering another round, or two dozen Krispy Kremes, but other than that no.
Thats meant to be a joke. When he was healthy, or what passed for healthy in a Kennedy, he was a damned powerful Senator, with influence in both houses and on both sides of the aisle.
Think he was a joke? The GOP sure didn't think so.
Agree with him or not, taking him seriously as a politician would have been wise.