Riku WOULD have offered to call their grandfather... but his Japanese wasn't really that much better than Roxas's. And it was crap when someone started speaking fast.
Riku stayed there with the twins, trying to amuse them a little, and talk with them until it started getting late.
"Roxas, is there anything you need before we go?" Riku asked, not pulling Sora off his chair yet. "Coffee? More blankets? Stuffed animal? Call one of us if your father wakes up, and we'll be over to get your for breakfast around nine."