My opponent is a big guy (pushing 300+ pounds) early 40's who makes very strange plays sometimes that make no since. I saw him play a hand the other night where he had limped behind a few other limpers with 23s. Four players checked to the river on a final board of Q87-2-6. He leads out and bets like 25% of the pot and gets looked up by A6s then talks about how "I thought it was good so I bet it". The game was mixed and he was confused as to why he could not play just the A with four diamonds on the board for a nut flush in omaha.

Preflop:
CO (me): $300 Dealt JJ
MP (him): $800

BTN straddles for $10, BB calls $10, MP calls $10, CO (me) raise to $35, everyone folds except MP who calls

Flop: (T65) ($90)
MP bets $75, CO calls $75

Turn: (T65) (7) ($240)
MP bets $100, CO calls $100

RVR: (T65) (7) (6) ($440)
MP bets $170, CO calls $170

With $30 worth of dead money already sitting in the pot, I'd probably even raise more preflop ($50 wouldn't be unreasonable, imo). But in the end, we still got it HU, in position, with initiative, against the table fish and set up an easy SPR to stack off on good flops.

SPR on the flop is 3 and we're against the table idiot. Board is extremely drawy. We're committed, and I woulda shoved the flop. As played, shove the turn.

I think your stack size or bet size is off somewhere cuz things don't add up by the river (looks like we've put in $380 into the pot, which is hard to do with a $300 stack), which might make a difference on how the hand should be played. I'm assuming we have a $300 stack, which makes the flop a super easy shove. ETA: Even with $400 stacks, we should really be stacking off early here with this SPR against a moron, although this would be made easier with a larger preflop raise.

GcluelessNLnoobG

Why does his weight matter? At 300lbs he's probably not as weak as you think because he has to carry around all that extra weight.

Also if you have $300 to start how did you have $380 by the river?

I started the hand with $380. The math is wrong.