I don't see why you are assuming/thinking that he would raise on the flush draw here. First, it's a mutliway pot and he's in position. Second, he's got some one, whom he's in position on, who is showing a bunch of strength. If he gets cute with it and raises, he's probably afraid you'll put him in. Also, he might be worried a little about the guy who is sandwiched having a set, but also hoping he does and then Villain gets paid off in two spots with his flush. It looks like a great place to just call. You don't have to buy every pot, especialy against a guy showing strength and another calling.

And I definitely check/fold that turn. Against two opponents, you're up against at least two pair. No way it's any good there. But if you have to bet out, fold to the all in.