His "True Colours" meaning he's not the man he claims he is... meaning he wasn't out to "make America again", like he said he would. In fact, the opposite. "Making America great again", does not mean destroying democracy, which was a model and the envy of the world. "Making America great again" does not include encouraging violence and starting a war in the country's capital building. "Making America great again" does not include claiming election fraud 8 months before the election even started. "Making America great again" does not mean trying to hold on to power, after clearly losing the election. By doing all those things, is no where near "Making America great again". It's more like digging a grave, and burying America.
And, yes, I guess you can say you're right, he has shown mental decline as well. Heck, what do you expect from a 75 year old anyways? I bet the guy can't get erection anymore unless he pops a few pills and drinks it down with a glass of chlorine bleach.
And you know what? I can bet you anything that Trump and Milannia or whatever her name is, will be divorced before 2024. That's if he's still alive by then.