"My parents keep offering to pass on their old, really old, laptops to family members and I keep persuading them that they will not be doing them any favours"
Wipe the hard drives, install Ubuntustudio and suggest parents donate to local digital arts/music/hackerspace
https://toplap.org/
https://jaromil.dyne.org/journal/zero_dollar_laptop.html
Core duo upwards is usable
Biting the hand that feeds IT
