Should students have a part-time job?

I have custody of my 16 year old brother. He would like to get a job. Here is my standpoint on this

1) I think only if grades in school are good to begin with, and don't go down alot after starting work

2) As long as the job doesn't make him too tired to get up in the morning.

3) As long as it's a job that follow child labor laws

I think it's good for a teenager to learn about responsibilities, money handling etc.