"Instead of impeaching him, just put him in a home. Just watch this," she said, referring to the president's press conference.
Trump, on Wednesday, had a tense exchange with a Reuters reporter who asked about what the president wanted the Ukrainian president to do with regard to former Vice President Joe Biden and his son, Hunter.
After Trump's initial answer, which focused on foreign aid in Europe, the reporter reiterated the question.
"I've given you a long answer, ask this gentleman a question. Don't be rude," Trump responded.
Trump later added: "It's a whole hoax and you know who's playing into the hoax? People like you and the fake news media that we have in this country -- and I say in many cases, the corrupt media because you're corrupt."
Behar, on Thursday, claimed that Trump was "unraveling."
Co-host Sunny Hostin added that impeachment was important because it was "forcing him to go through and withstand an impeachment inquiry as well as campaign."
Behar has a history of attacking Trump's mental faculties. She previously suggested that Americans should "get with the program" and agree with her view of the president's intellect.
"I mean, how many more people does he have to fire and how many more of them have to say he's stupid before Americans get with the program and get this guy out?" she asked in September.