Tell me what daddy thinks, does he think more of this 18 year old brat?

My kid sisters 18 and really gets on my nerves. Shes actually a model part time when shes not getting straight As in her law degree at uni. She just turned 18 yesterday and daddys just got her a new golf car and as she was pestering him he caved in and said she could stay in a penthouse which he owns 5 minutes walk from the uni in the city centre. He never allowed me do this, i only got one of his one bed apartments in the complex when i was in college and he only bought me a modest two bed town house when i graduated. Why is she allowed stay in a 3 bed penthouse. Also i know for a fact she is seeing a guy from the wrong end of town and i'm thinking of telling daddy..he wouldnt be impressed. Why is she being treated like this? I'm 26 and working in daddys company and although he owns the firm i only get paid slightly more than the others....she got away with murder when working as his pa last summer and totally upset the older woman whos his pa for years. Tell me what daddy thinks