Applied at Walmart for online pickup and delivery

I recently left my job because my manager wasn't treating me or my coworkers well, and I've been on the hunt for part-time positions for about a month now. So far, I've only heard back from Walmart, which is great news. However, my older brother, who works there full-time, is really against me taking the same role in online pickup and delivery. He gets visibly upset when I mention my interview with them, claiming that the manager is bad and that I wouldn't enjoy the job. This has left me puzzled because we generally have a good relationship at home. I decided to hold off on accepting the job offer because I don't want to cause tension between us, but I'm starting to wonder if I'm making the right choice. I could really use some advice on why he might be reacting this way and whether I should just go for the job regardless.