If she cares to, she can watch him climb down. It'll take a while. He's being very careful.
She advances further into her room when he has gone out the window and she supervises his descent.
...and about a third of the way from the window to the ground, one of his handholds crumbles away just as he's reaching for the next one. He flails and manages to grab onto the protruding corner of a stone block, which promptly snaps off in his hand. Despite both of these unhappy accidents, he still manages to cling flat to the side of the tower for another couple of seconds, until his satchel slips off his shoulder and unbalances him and he falls.
Rapunzel is alarmed - she could throw him her hair but it's mostly downstairs - she hauls on it but he's on the ground before she can even see the ends.
He doesn't scream or anything - he cries, but very quietly. She won't hear it and she might not even be able to tell by looking, from that high up. What is visually obvious is the fact that both his legs are bent in ways human limbs do not normally bend.
Rapunzel keeps hauling on her hair until she has it all.
She throws it onto him.
"Hold still," she hollers, and then she sings, very very quietly.
As soon as she's uttered the last note she starts hauling her hair up again.
It takes him a minute to catch his breath.
Then he yells up to her, "...Thank you...???"
"You're welcome don't tell anyone please," she says, hair halfway up.
"When she was pregnant! The queen got sick! And someone brought her a magic flower! A glowing! Golden! Magic flower! And she ate it and got better and had the princess! And the princess was born really blonde! And she'd be about your age!"
"My birthday is in the summer and my name is Rapunzel and I have a mom!"
He pauses to catch his breath again, then adds, "King Cearl and Queen Ranae are really upset about losing their daughter! The queen still cries about it, it's really sad!"
"I'm a forest hermit because if I leave people are going to kidnap me and abuse my hair! You could be making this up!"
"Does your mom use your hair? Do you have any way of telling if she's been making things up?"
"Of course she uses it! I use my hair when I get hurt too - I'd let everybody do it if I could trust anyone! She's raised me my entire life!"
"Raising you your entire life doesn't mean someone's not lying to you! Believe me, I know!"
"It's better credentials than breaking into my bedroom half an hour ago with something you stole from the king and queen who you're so concerned about now!"
He throws up his hands. "Fine! Stay in your tower, magic glowing flower girl! Just tell me, if you'd let everybody use your hair, what are you afraid of somebody doing—keeping it all to themselves?"
"I'm afraid of being tied up and force-fed so I don't escape while half-willing soldiers are marched past my hair twenty-four hours a day to keep wars going longer and cheaper and for less reason! I'm afraid of being a bargaining chip in international politics with no say in the matter! I'm afraid someone will chop it off my head and it will stop working and then no one will get to use it at all and one day I'll die! It doesn't sound from your description like the queen's really responsible with healing magic if she ate that flower instead of going to visit it!"
"The queen was too sick to get out of bed! People went and got the flower for her because they like her and they didn't want her to die and leave the kingdom without an heir which by the way it has been for eighteen years anyway! Here's an idea, wait until she's about to die again and then come flouncing into the capital, no one's going to use you as a bargaining chip when they're busy making you fucking Queen! That was a sarcastic suggestion in case you can't tell with all the yelling! It'd work but it'd be a pretty awful thing to do to her!"