Clearly she must correct their tragic deficiency of cooking experience. With lots and lots of delicious food.

Okay, grandparents are pretty nice. The two eat very appreciatively. 

"You could open a restauraunt!"

"Oh, thank you dear. But I'm much too old for anything like that, these bones can't bear to cook except out of love."

Old is still weird, but the twins keep quiet. 

"I mean it's really good. If you would be so kind as to make us some stuff to take along I will give you a jar that's bigger on the inside than the outside. That could come in handy right?"

"Oh, I would have cooked my Grendal and her friends food for sailing anyway."

"Then we'll give you the jar as a present, right, Nemo?"

"Sure, sure."

"You have any chores and stuff you want done?"

"I wouldn't complain if you two fetched me some firewood and well water... But you deserve a break, you don't have to."

"It's not as hard for us as it is for human children, really."

"If you say so. Well, you don't have to."

Well water and firewood is fetched at short notice.

Grandma Erlund smiles at them in a very Grandmotherly way and the profusion of food continues.

When it's time to leave she offers surprises them all with a hug. Even Nemo mostly accepts it.

The twins return it as hard as they can without hurting her.

"You're one of the nicest people we've ever met." She sounds so earnest. 

Rilah jokes, "It's the job of a grandma to be the nicest, you know."

"So what do you call your mother's mother if she isn't nice?" It's hard to tell if she's joking. 

"You call her-" Rilah's voice goes low and facetiously angry. "Grandmother."

"I'll remember that."

"Does it work for, ahem, grandfather, too?"

"Indeed, yes!"

"Mother, father."

"I don't think I'll ever have to use any of those. If I do something has gone terribly wrong."

"I'd have to find our father first."

They joke around for a while longer. Grandma Erlund excuses herself eventually... Old means tired. "I've got to save up energy for making good sailing food for you dearies."

"Thank you."