senile

I asked him about that moment just after it happened, and had asked him whether the president was senile the day before.

In scathing remarks, Sacks called the president “sleepy and senile” and a puppet manipulated by a deceitful White House staff — which has continuously gaslighted the country by hiding his failing condition.

“I could put together — and people have — a video of Trump looking absolutely just as senile,” Maher said.

Russian state media have consistently mocked the current US president as "senile" and a person not really in control of events.

Especially if a person seems to go senile very quickly, check their vitamin B12!