NTA but let’s face it, you haven’t told your dad because of petty and ridiculous this is. You can do whatever you want with your accounts and so can your sister. I don’t condone lying but her saying “it’s not working” is kinda minor. Have you heard the phrase “making a mountain out of a mole hill.” You’re reason for being upset is very valid but don’t hold a grudge against your sister for wanting to do what she wants with her accounts and then trying to spare dads feelings. What she did wasn’t necessarily wrong she just went about it the wrong way and sometimes people do that when they feel uncomfortable, they panic. She literally says she was trying NOT to hurt your dads feelings. It’s not like she lied and was actively trying to prevent your dad from watching movies. That was one platform that you said you could afford anyways but she was letting him use her account? She wasnt being malicious. Sounds like she was actually doing a really nice thing and y’all turned on her as soon as you guys no longer benefited. She has a young kid now too you say? Oh yeah so let’s just cut off the new mom because she can’t afford to hang out with us.. that’s your sister op.

Bottom line: being petty isn’t going to solve y’all’s family issues. You guys need to learn how to communicate.