I would actually agree with the assessment of his mental aptitude for the job (although I would argue he was never mentally capable of doing it). If that is the reasoning they use, then I expect those underneath him who allowed him to remain in power need to be held responsible for all the laws he broke and they stood by and watched while they didn't lift a finger to stop him, and in fact aided him in conducting.
I think this would be the best outcome possible. Trump gets to spend the rest of his miserable life doped up on drugs in a mental institute somewhere without access to the internet, TV, or social media and the rest of his administration gets to spend the rest of their lives in jail for allowing it to happen. Maybe that will get these people to think twice about allowing this to happen again.