Or, perhaps, he is just pushing for the Democrat establishment to up the ante for him to take a dive.
Bernie is betting that Biden's deteriorating mental condition will force him out before November. Bernie wants to remain standing as the runner up and presumptive replacement with more earned delegates that anyone else. That would put the party bosses in the position of overriding the voters to throw the nomination to someone else.
I’ve missed all the debates up til now but with two it might be tempting to watch until I think about it a bit. Half or more of the time would be taken up by Bernie ranting. Too much for me regardless of potential entertainment value of stumbles by both or either candidate. The high or lowlights are all one needs to see.
Right now Bernie has the Democrat hierarchy over a barrel. Hes going to milk this for all he can and why shouldnt he. Bernie is a con man dealing with a bunch of con artists themselves. They need Bernies voters in November and they need to keep Biden from debating anyone period! Comrade Sanders knows hes got a big payday ahead of him!