He was confused and kinda enjoyed her
"Ok so..."
She looked around at the pools
"...That oneee leads to the north-yeah-yeah ok cuz that's where the narwhale pod was-aaand that oneeeeeee leads to the kelp forest-ooh, don't wanna go back there again....huh...um-hm....shit dad's gonna kill meeeeee-"
"Why don't you just stay with me?"
"Uh-okay well first of all-no I gotta go home-and second of all, um-tail."
She lifted her tail out of the water a bit for visual emphasis
"Aaand third of all-I don't even know you! Aaaaand none of this even matters because I'mmmmm imaginary!!-"
She ducked her head under the water again
He grabs her hand
"If you're imaginary, then I don't see a reason why you can't come with me"
He smiled
She looked at him
"....Alright I know you know I'm not imaginary-"
"No you're just a hallucination, so c'mon"
He lifted her with just one arm out of the pool
"EEP! W-HEY!"
He then carries her on his back and starts walking
"Oh hey, you seemed interested in these right?"
He takes off his sunglasses and gives them to her and continues to walk
"W-ooohhhh..."
Aaaand she was thoroughly distracted.