Over on Truth Social, Il Trumpe truthed this out:

Text:
So, we are forced to spend time and money on fighting Crooked Joe Biden, he polls badly after having a terrible debate, and quits the race. Now we have to start all over again. Shouldn’t the Republican Party be reimbursed for fraud in that everybody around Joe, including his doctors and the Fake News Media, knew he was not capable of running for, or being, President? Just askin’?
This really doesn’t sound like Trump (which makes it all the more delicious), but he really does want someone to reimburse him for his bad campaign choices. He really is that venial and stupid.
You can just smell the fear.

As Heather Cox Richardson said, Biden has an exquisite sense of political timing.
Really. I believe he saw this coming. In a recent interview, he was asked “What will you think if you continue your campaign and lose to Trump.” He answered “If I did my best, I’ll be at peace with myself.”
Drumpf and his friends must have been deliriously joyful at that. ROFL.
(Truth in advertising: at the time I was aghast at that answer: I really thought he had lost it. I was sooooooooooooooooooooo wrong.)