We don’t need a body language expert. Biden self-identifies as a Rat. That means he always lies. Well, when he can remember to do so.
I am a body language expert, and I can unequivocally tell you that not only is Biden being deceptive, he is openly lying. He has a distinct characteristic that gives this away and makes him easy to spot as a liar:
His mouth is moving and sound is coming out.
Note that both are necessary components, as Biden spends a lot of time imitating a just-landed fish with his mouth opening and closing, but no sound.
I suggest a high likelihood of brain death.