Very angry with my sister

So my sister worked at McDonalds between the ages of 18-22 and I think she worked around 16-25 hours a week and didn't give a penny to my father. This was around 2007-2011. ZERO money.

And my dad had work next day at 5.30am at the factory and he had to pick her up from mcdonalds at 11.30 at night with few hours sleep.

Also she's worked as a marketing assistant between 2013-end of 2016.

Since the end of 2016 until now she's been working as a marketing manager and she is on around £31k and she still hasn't given a penny even after 4 years of good income.

She has since the last year one-two days a week helped out preparing food and this only since the last year. I help out with the food everyday.

My dad has had a hard life and we lost our mother in 2001.

I remember I paid for the sky monthly because I wanted to make him happy and felt sorry for him because he is lonely.

She does go out a lot, goes on holiday 4 times a year, london once a month, goes out every week to a restaurant.

What irritates me is that my father makes something maunually struggling for 1 hour everyday while coming back for work where he can get it from Asda for £10 a week. My sister see's this and why can't she give him that £10?

I give my father a helping hand and I've not yet graduated, why can't my sister help out? Even £10 a week would be useful.

I got the sky to make him happy.

Once again, you never know what can happen and if he is gone tomorrow and I'm sure she wishes she could have helped out.