[Heisenb3rg]

river is a slight spew, let's say he calls every hand including T high.
Enter the board and your hand vs a random hand on poker tracker.

Random hand equity = 66%
You = 33%

So this is assuming he doesn't get agressive with any twopair+ hands as well as calling hands with 7 high on the river, I think it may balance.

Since he's so loose passive, he wont bet everything that beats you either. In fact if the pot weren't so enormous you can probabily check/fold to a player like this.