He boasts about his use of Rule 65 of the Federal Rules of Civil Procedure to try to boot Trump off the ballot.
But, he downplays one thing.
The Rule grants a preliminary injunction or a temporary restraining order. (Italics added.)
That's the part that Castro isn't really talking about.
After your TRO is up, you still have all the normal legal heavy lifting to do.
As for his case soon to hit SCOTUS? Castro has to clear the "standing" hurdle, which he may well do, and the "ripeness" hurdle, discussed by me before, which he almost certainly will not.