Behaviour changes can apply for some young people during their teens, yet your sister’s recent behaviour does carry risk and as you state, really isn’t on regardless of a person’s age or circumstances. While it’s admirable that you recognise this and are feeling the need to set some boundaries for and with your sister, it’s important to note that the primary responsibility for this lies with your parents. This doesn’t mean that you shouldn’t try and help set those boundaries - particularly in areas that directly affect you and your stuff. While you and your sister are under 18, and while you live under their roof, your parents have the right to negotiate and set behavioural guidelines and expect you to behave according to those guidelines. In addition, they have a basic parental responsibility to maintain their provision of care and guidance, and generally promote the well being of their kids. A health and safety focussed discussion of the dangers of sneaking out at night and taking alcohol or other drugs would be an example of this. As such, the first step may be for you to come together as a family and work out strategies for dealing with your sisters’ current attempts to push her rights as a teenager: rights which she apparently wants to enjoy without accepting any accompanying responsibilities, and without any regard for the rights of the rest of the family. Helping improve your sisters behaviour without becoming abusive is a challenging - yet worthwhile - aim. The following steps may assist in this process: First, your parents need to set up the expected behavioural rules and guidelines and make sure everyone understands them. Making the discussion about ‘family functioning’ and not ‘younger sisters’ behaviour’, would hopefully make such a session easier for your sister to stomach. Your parents need to state their reasonable expectations calmly and firmly. In this case some obvious examples are ‘no sneaking out at night and no stealing from each other’. Rules like these should be non-negotiable. There may be other guidelines which you or your sister can negotiate with them. Secondly the family can discuss what the consequences for infringement and rewards for sticking to the rules and guidelines are. Consequences can involve loss of privileges, suspension of entitlements or withdrawal of more basic rights in and around the family home and the consequences can become increasingly severe if rules are repeatedly broken, or decreased for compliance. Rewards can become the sought after ‘bonus’ for consistently positive actions. Your parents will need to be willing and able to follow through on them. Likewise, you can work out the particular things you need your sister to stop or start doing to you. Try to discuss this with her calmly and clearly first. Then check out if there are consequences and rewards you can help motivate her with. For example, do you give her lifts to places? Are there things of yours that she likes to borrow (not steal). Regardless, you will need your parents backing for any boundaries you try and set with her, and again your parents will have the final word. Finally, setting up this kind of framework will give your parents a better chance of effectively communicating their expectations with your sister into the future. If your sister breaks the agreement she only has herself to blame, and the consequences can take the place of people yelling and fighting with her. She will probably do most of the screaming at first, but will eventually realise that this just gets her into deeper hot water - consequence wise.

None of the above is easy. It is basically asking the family to ‘re-program’ how it operates in a number of areas. Your sister’s behaviour could get worse before it gets better because the family is trying to set limits for her, and - in some areas - she’s already been getting off scott-free. However, this is important for your family’s sanity and for your sisters’ development as a person. If your parents need help they should contact Parentline phone counsellors in your state or territory for information, support and referral. It might be necessary for the school to become involved at some point too. Meanwhile, you have a right to have your property, privacy and safety protected, and to get on with your life without abuse or having to take the ‘parenting role’ in relation to your sister. A Kidshelpline phone or e-counsellor (1800 55 1800) could help you deal with your frustrations, and discuss strategies too.