1/3, 9-handed

Extremely loose-aggressive table. Typically any two cards 9 or higher will open raise from any position, except for 1-2 decent players.
Approximately 40% of hands are 3-bet pre-flop.

MP (30yo black male, $400) opens to $15
Hero ($300) calls in the CO with 7-7
SB (35yo white male, $850) 3-bets to $65.

Up to this point, SB has 3-bet every single hand that H has raised or flat called - from any position. SB probably knows that H is the only players on this table who realistically fold to a preflop 3bet.
There is little to no fold equity either pre-flop or post-flop here.

MP folds.

What do you do?

What should be your shoving range here?

What should be your flat-calling range here - if any?

When you say Villain has 3bet "every single hand Hero has raised or flat called", what are we talking here? 20/20 over the last hour? Or 2/2 over the last three hours? The more the former, the more I'm fine going with it. The more the latter (and in general), the more I'm just folding.

ETA: Doubt we should be flatting anything for this large a percentage of our stack.

GcluelessNLnoobG

More like 7/8 over the last few hours and moreover, a high percentage over several sessions.

What's he shown up with?

GcluelessmaniacnoobG

He doesn't show his hands. Sometimes he shows one card and almost always it doesn't connect with the board.

My flatting range would only be AA. Everything else is shove/fold. Shoving 66+ and AJ+. I GII here.

Is the single card often < T?

In the end, you've described him as a maniac. If that's the case, I'd probably go with it (although I'm guessing 77 is near the bottom of my going-with-it range).

GcluelessNLnoobG