I was playing a very loose 1/2/5 live PLO game ($200-1000 buy in) when the following hand came up:

An EP player opened to 15, 3 players called, I called on the button with A533ds and the big blind and the straddle came along (pretty standard). So 7 players took the flop - pot $106. The flop came 322, giving me top full. It was checked to me and I bet $75 and only the big blind (a decent very loose aggressive player) called. The turn (pot $256) was an A, the BB checked and I bet $178 and the BB called. The river (pot $612) was a 6, the BB checked, and I bet $378 and BB check-raised to $800 (with $1100 effective stacks).

What should I do in this spot (obviously calling or folding are my only options)? Is the BB only raising for value with AA or 22? I'm getting 4.24 to 1, which means I only need to be right less than 20% of the time for a call to be profitable. But is he ever raising with a hand I can beat? I highly doubt that he would take the line of call flop, call turn and check-raise bluff river.

Any advice would be greatly appreciated.