This is just my guess:
Howard will have multiple meetings over the next two months. A lot of them will involve Robin.
If Robin wants to come back in 2026, then it's easier for Howard to re-sign. If Robin is done, then Howard is.
Howard's next live day is 9/2. He's not going to announce anything on that date, BUT...if we get deep into October with no announcement, then I think the chances of him coming back increase.
Nobody can end 40-some years of a career without a huge announcement.
When he went to Sirius, everyone knew with well over a year. Not just the fans, of course, but the affiliates all needed a plan for Jan 2nd, 2006 for their on-air show, sponsors, etc etc.
UNLESS...Howard privately says he's done so the team can all have a few months to get another job. There'd probably have to be some sort of penalty if something were to leak out. It'd be near-impossible to keep the news secret.