Corrected entry: Lucy's dad brings up the idea for her to paint his shed. The script should have had Lucy wanting to do that on her own - without that prompting there'd be no need for them to bother repainting it every night, which they clearly don't enjoy doing.
Question: If Lucy's father was the one that gave Henry the Beach Boys CD, how could Henry take that as a sign that Lucy remembers him?
Chosen answer: Lucy's father previously told Henry that she only sings on days that she meets him - then you see a flash of her painting in the garage, singing a Beach Boys song. Right before he hands Henry the Beach Boys CD, he tells him that she's even singing again. Henry realized as he listened to CD - maybe if she is singing again, she is thinking of him, hence, remembering him. (It happens to be the same song that she was singing in the garage that's playing on the boat when Henry turns around to go back. It's called 'Wouldn't It Be Nice').
Why wouldn't the father just tell him directly "hey she's been painting and singing again, so she probably might remember you"
Question: What would happen if Lucy stayed up all night and she was with Henry? Would she all of a sudden forget him or would it happen very slowly?
Chosen answer: Apparently, she loses all her daily memories when she enters a full sleep, so keeping her awake would have given them a chance to see each other for longer periods.
Then my question is what about the naps during the day that she takes?
Naps would reset her brain like any other sleep.
Correction: Lucy's dad and brother go to great lengths to re-enact everything that happened the day of the accident, including having Lucy paint the garage. They don't really want to do any of the things they do on that day, including eating the cake and watching The Sixth Sense.
BaconIsMyBFF
But why wouldn't they just go and pick the pineapple instead of dad prompting her to paint the shed? Then he wouldn't have to paint over it every night.
Because painting the shed makes her happy. They are sacrificing their time and effort, at great exhaustion, to keep her happy.
BaconIsMyBFF
Going to pick the pineapple puts them in public and gives a much greater chance of her finding out the secret and having a bad day.
LorgSkyegon
It absolutely does, and it does lead to some issues when she gets pulled over for expired tags. Dad and brother's plan was not very well planned out and certainly wasn't smart, but that doesn't constitute a mistake in the film. People make poor decisions all the time.
BaconIsMyBFF