[Wally is likely too wrapped up in his own grief still, but Jay definitely realizes how difficult this is for Hal. He's trying to be present as much as he can be for multiple reasons - wanting to search for Barry, not wanting to give up on him of course, but also not wanting to leave Hal alone with his thoughts for too long.]

We're damn sure not going to write him off as dead without a body. [Jay agrees, because he gets the sentiment, but also because he thinks if he tried to argue the point, he might actually break Hal.]

I think it's time to start looking out at other possibilities. Time travel, alternate dimensions...