He talks as if he <know/knew/had known> everything

[moazzam]

Hello Sir,

He talks as if he ______ everything.

Context:
Suppose, a student is talking about the future plans in the class room, e.g, he says; "We, the students, will go to a restaurant for dinner sometime and we'll be having a great fun there". A second student named John is sitting nearby, he argues; He (the first student) talks as if he ______ everything.

What to be used here? knows, knew or had known?

Thanks.

[Alan]

Either 'knows' or 'knew', the second (past subjunctive) implying less belief on the part of the speaker in the truth of the statement.