Via points at a sink full of water with a ladle dipper in it.

...Yeah, he's really thirsty.  Gulp gulp.  Trying not to touch the ladle.

It has a mineral-y taste but is basically fine to drink.

Okay.  He thanks the halflings and heads back to Belmarniss's room.  ...Or tries to, given that there's no light in that one.

Hopefully he finds it! And isn't sitting in some random family member of hers's bedroom!

Are the hammock and the books where he remembers them to be?

With enough feeling around: yes, congratulations!

He'll go back to relaxing in the hammock and quarter-heartedly trying to do magic again.  This time focusing on trying to do the light thing specifically.

When that doesn't work he passes a while trying to brute force some vocabulary associations without the use of text.  Eventually he comes up with a little bilingual rhyme which he's pretty sure he'll be able to remember tomorrow unless the forgetting happens magically.

After she's been gone for nearly eight hours, Belmarniss reappears and lights up a convenient rock for him. "All good?"

He's aimlessly sculpting the air when she walks in.  He might have somewhat forgotten that just because he can't see his hands doesn't mean she and her family can't.

"Yep."

"...what are you doing?"

"... It was dark and I was.  Bored."

"That's legit, I was trying to like, give you time to settle in before I put you to work but I can send you with the halflings hauling water tomorrow and pitch my mom on borrowing you the next day, since I got you some normal clothes to change into." She tosses him a bundle. Hangs up her cloak again. "I'll step out while you figure that out, shall I?"

"Thanks!"  Can he make sense of these clothes.

It's a long gray hooded robe with a belt - more belts? - a belt and some other kind of cinch he's meant to do something with? - and a mysterious rectangle.

Okay, the robe is pretty straightforward; for the rest, what about this configuration - hm, that's not right, and neither is this - this one doesn't feel that off?  "Decent!" he calls, once he thinks he is.

In she comes. "- the cinches are for your sleeves, so they don't dangle or catch on things."

"Oh."  Uncinch uncinch recinch recinch.

"I've decided to wait a while before trying to sell your stuff; I don't want it to look like it had anything to do with you or like you might be, uh, interesting."

"Thank you."  Sleeve fidget.  "I didn't mind being bored," he tries.  "I mean, uh, I want to be helpful, and it would be really good if there was more water here - do you guys know about germs? - but, I mean, I could have stayed in the kitchen.  If I'd wanted."  (To stand around and be made fun of, for - well.)

"What's a germ?"

"They're really small things that live on everything, and some of them are fine but lots of them will make you sick.  But they come off with soap and water, so you can stop a lot of them from getting inside you if you wash your hands after touching certain things.  And then get sick less."

"Wizards do get sick less than regular people, but so do clerics and martial adventurers who can't cast Prestidigitation, so I don't think it can be like that here."

"...I would still feel a lot better if I could wash my hands sometimes.  Do you have soap?"

"I've seen it in fancy places but it's kind of a waste of perfectly edible lard."