So my husbands little sister is a junior. She’s a great kid and never gets in trouble. She’s been asking for a month or so if she could move in with us. At first I was fine with it cause her home life isn’t that great. She suffers from depression and her mom thinks she’s making it up and pays no attention to her. On the nights she sleeps over she says we make her happy and her depression doesn’t get that bad. So my question is would you do it? Would I be taking on the mother roll? Should I be allowed to tell her what she can a cannot do

Also wanted to add her mom is ok with it. My sister in law knows what she would need to do to continue living here (school,chores etc). My main concern is my husband works up north so it would be just us most of the time. & I’m not sure If the situation arises am in the right to punish her? My husband says yes but idk I just would some like more opinions on that