Initially, he wanted to modify the 25th Amendment, but even he soon realized that wasn't going to go anywhere, so he's trying a different approach that also won't go anywhere:
Rep. Earl Blumenauer (D-Ore.) filed the bill during the House's two-week April recess to empower former presidents and vice presidents of both parties, in coordination with the sitting vice president, to determine if a president is fit for office.
Blue's very concerned about Trump's psychological health, it seems. On the one hand, yes, Trump does some pretty strange things; it's a pretty safe bet, however, that Manure would have no such concerns had the harridan been elected.