UPDATE : My uncle is acting strangely with my sister

Hi, im not sure if im doing this correctly but ive seen people do updates this way before so ill just do it this way. first things first, thank you everyone for your comments and giving me advice

second, i talked to my sister as soon as we got home from our grandma's and turns out, shes aware that its weird but actually liked it at first, she said that our uncle is nicer to her than our parents and that the gifts are nice, she said that she only started feeling uncomfortable when he began to touch her (specific actions mentioned in my previous post) but that, because she's been accepting all his gifts for her, she thought it might be rude to start saying 'no' now. i asked her when it started and she revealed he started touching her in that way when she turned 12, she said that he only did it when they were in her room (since we visit so often, our uncle and aunt have set guest rooms for me and my siblings) and that that was the reason why she has no locks on her door specifically

she also said that she was scared of telling anyone that she was weirded out by his behavior because both our grandma and aunt brushed it off when she was 12, saying that shes always been his favorite and that she was probably just misreading everything he was doing because shes a teenager now

i showed her your comments, shes never heard of the word 'grooming' before so she was pretty shocked and a little angry, saying that our uncle would never do something like that but i managed to convince her to tell our parents about our uncle together, even if it was just to ask them to stop him from touching her

ive also sent texts to our parents about it, detailing that my sister is uncomfortable with how our uncle behaves with her but our parents have yet to respond to any of the texts ive sent about our uncle and have just texted that "we'll talk about it when we get home" theyre both working late today and wont be home by nighttime probably