this question is most likely best answered by a recovering addict
but my opinion is that the teenagers brain isnt even fully developed and their reasoning skills are lacking .........so how can she guide an adult?
today my husband told me that his therapist ( a recovering addict) has told him to find a new sponsor.............and it needs to be someone who
1. has at least 5 years clean
2. is working the steps
3.that has a sponsor thats working the steps and that HAS a sponsor working the steps
4. that his sponsor needs to also be someone he can get face to face time with weekly not just passing at meetings
seems to me that the idea is that he needs someone with solid recovery time and also the guidance of others with recovery time and experience
So I'm thinking that the same would be good advice for your sister................it makes sense to me
Best wishes to you and your sister.