It’s often said that “alcoholics don’t have relationships, they take hostages” and it would appear that you and your parents are HER hostages in your own home.
Alcoholics manipulate, she’s manipulated you into allowing her to stay right where she is. A few weeks ago she was trading one addiction (booze) for another (pills) has she given up both, that you know of?
Next time she manipulates by threatening suicide or punching herself in the face or cutting, call the police and have her removed into the hands of PROFESSIONALS who can really help her. You are not equipped for this nor do you or your parents deserve it.
Has she gone to AA? Has she sought out counseling? Has she done one single things except not drink (that you know of) to help herself??
If you are struggling with asking her to leave, then for once with this bad situation put your parents FIRST, put yourself FIRST……….just like she is doing!!!!!