My sister in law is probably the most annoying family member I have. She's 23. She lives at home with her dad, which wouldn't be so bad if she simply couldn't afford to be out on her own. But daddy said he'd pay for her to stay with him if she was going to school, so...she didn't graduate highschool til she was 21, and she has been to college not once, but twice. She gets daddy to buy her a bus pass every month, but more often than not mooches a ride from him or her mom instead.
She's a total Munchausen case, too. Not for serious stuff that'll put her in the hospital, but whatever puts a label on a supposed ailment, and gets attention from friends and family. Said illnesses usually come with prescriptions, but they're not necessary to make her happy, so I don't believe she's an addict. She'll gladly tell anyone that will listen that she has this, that, and the other fucking thing, and she'll often add in how many pills she has to take every day. I don't buy into most of it. I'm sure there's a few things that are valid, but certainly not most of the shit she has.