I can’t stand my sister. I have no desire to be kind to her at all.

She’s 40, she moved in with my mom and just got off meth. (For the 100th time). She does this every once in a while when her boyfriend kicks her out. She will come and be sober and work and then just leave for months and come back to my moms with NOTHING. No money, no job, literally the clothes on her back and then expect handouts. Between her, her ex husband and her boyfriend now they have lost 10 kids, 6 being my 4 nieces and 2 nephews. I have no sympathy for her. I want to encourage her which I do but it’s hard cause I know she’s gonna just leave and go tweak on the streets once the weather warms up and her boyfriend asks her to come back. She literally had 6 chances to change and not ruin my nieces and nephews life and she didn’t care. She always chose the drugs. all I see when I look at her is a tweaker..... not my sister and I can’t be nice...... i try because she is nice but I CANT. I hate her. idk if I’m wrong though or if it’s justified.