My,cousin was missing for 2 yrs. And was on crystal meth for a long time but,she also was mentally abused,and most likely sexually abused.She is not the same anymore she lost her self being,and is always wanting sex,she steals,lies,and agrees to everything,she doesn't know who she really is anymore but she does remember her family,but she doesn't have any respect for herself or others.some how I need to find out what really happened to her,even though she is not all there she is still my cousin and I love her.. but honestly I don't know if it would have been better us finding her dead or like the way she is now..

NO, and I do mean no, you don't need to find out a thing, you want to find out things. She needs love and professional help. She will not ever be the "same" just as you are not the same as you were 4 years ago.

So what is being done by her close family to have her evaluated perhaps put into a drug detox center ?

Im glad you still love her. And this sort of things happens a lot often then you would think. The thing is she has to want to change and become better than she is now. Talk to her see what's going on.