good for someone—
1. beneficial or helpful for a person:
- These classes are good for students who work better at a slower pace or are fairly new to computers.
2. (of food) nutritious or wholesome for people:
- Green leafy vegetables are good for you. They contain important nutrients that keep your children healthy.
good to someone—said of smb. who is kind to a person and willing to help:
- She has been good to me and my family when we were struggling.
Note: The expression does not correlate in meaning with the phrase good with someone—efficient in dealing with people:
- She is very good with children and will be assisting me with my class.