I doubt it. While some people think he'll be dead by then, I'm inclined to suspect not. However given his observed mental decline, I suspect that he'll be even less coherent 4 years from now. He's currently 78, and would therefore be 82 by then (birthday June 14th 1946). He's already got a number of age-related medical issues, such as needing to wear adult diapers and said mental decline.
Behind the scenes is be surprised if he didn't have some cardiac problems, even minor ones, and thus was on something for them, such as blood thinners or cholesterol meds. I don't know if it's been verified that he's on Ozempic, but he sure has lost a lot of weight lately and I don't think it's from exercising.
I do expect that he's never going to shut up though. If, hopefully, he loses this election, he's not going to just evaporate. People are still going to give a damn about what his opinion is and who he endorses, especially his cult of followers, but also the less overtly extreme conservatives.
As a general rule, cults built around a singular person, AKA cults of personality, tend to crumble into dust and fade into history once that personality is gone. However, some cults outlive that person because someone else is there to pick up the slack and reform things just enough to make a going concern of the cult. That's how Christianity started, that's how Protestantism started, and if you look into it, just about every other major, lasting "religion" that had branched off of the Christianity family tree. It also goes for political, cultural, and social movements, which can be cult-like without the religious aspect being an absolute requirement, although ir can be very strongly intertwined. I don't know where the Cult of Trump will go once old age finally catches up to him, I think it's likely that it'll be reabsorbed into christo-facism because the two feed off of each other pretty strongly.