Ok need some help in this area ?

ok my auntie youngest son my cuzn brother his in high school his been hanging around with his uncle abt his age my nephew there both abt 18 and 17 will my cuzn brother got cought a school with smoking (marry jane) but he when thro drug councliing but nw i and my family hav been talking to him abt drugs and what it wud do to him and this happen in march and we all no that he has not tought the stuff but his mother and older sister thnks he is still using so no his older sister has signed him up for drug treatment for 6months and she blames my nephew from my point of veiw the boy stay home and play vidoe games and help around the house having them at the house we the family know what there doing at all times is it not rite for the older sister do that to him she is not there to watch him cuz she works two jobs and we the family tryed to let her know that he hasnt botherd the stuff and she will not do anythnk abt the younger sister run around town while the boy stays home it that so wrong for her to do that to her brother insted of the younger gurl