Rey is absolutely out like a light, but Cassian is very content to just stretch out that chance anyway. He lowers her a little, just so his hand doesn't get stiff, but he doesn't stop cradling her.

He chuckles quietly, because the baby really does look the equivalent of wasted on milk. Literally the least Cassian can do for Jyn is get her alcohol. "I'll buy you one. Maybe even a few." He pauses. "Though we might still have some, if you really want one now."