Final answer:
The word that could replace "nice" to show that Theo is always doing things for other people without being asked is "charitable".
Step-by-step explanation:
The word that could replace "nice" to show that Theo is always doing things for other people without being asked is charitable. Being charitable means being generous and helpful towards others, often by giving money or resources to those in need. It implies a willingness to help without seeking anything in return, which aligns with the description of Theo's behavior.
Learn more about Word choice to describe someone's helpful behavior