I have a team of 3 including my Manager and we releases once a week. Recently I noticed that my co-worker take work home for the Weekend to finish and have a time buffer in the next week. Also can see lots of his check ins, slack messages, etc on weekends. However I can see the good intention in that I can't help to think that this actually goes against him and the team.

Note- my coworker has joined before couple months & He is Indian. I have observed from past experiences that lots of Indians do work on the weekends.

These are my arguments:

1. This is setting higher expectations for manager that no matter whatever difficult work it is, Our team is going to get it done within the deadline and if not, they will finishes in the weekend.
2. I don’t work in weekends so basically on Monday i do have lots of to do’s for the day while other guy’s comment is he is done with all the work.
3. My manager doesn’t has the expectations that I should work in the weekend but who knows!! Could be just matter of time until he asks me too.

Is my view of the problem correct? How to deal with this situation? My responsibility is not to tell anyone to stop anything.