AITA for inviting my nephew and niece to stay with me at a nice hotel and treating them to fancy dinners, but not their older sister?

I (35M) recently went back to my hometown for a two-week stay. Mostly for work reasons but I also wanted to surprise my nephews and nieces cause I haven't been back in a few years.

My parents came from lower class backgrounds and worked hard to provide. I took advantage, finished school, moved abroad, and am now blessed to be in a position where money is not an issue. I'm single with no kids by choice, and make more than enough to live comfortably. I live modestly, though I have a large budget when it comes to travel, food, and socializing.

Meanwhile my siblings are notoriously bad with money. My sister in particular always prioritizes wants over needs. She's always broke, no matter how much she earns. Her kids, suffered as a result, sometimes missing meals or have no running water at home cause my sister spent it all on I don't know what.

Being the cool uncle I am, I like to spoil my niblings when I visit. They're like the kids I don't have. We'd go to restaurants, theme parks, and other fun stuff they normally can't afford to do.

I’m cool with this. Quality food, nice hotels, and entertainment are all things I take for granted now, but it’s the equivalent of a celebrity lifestyle to my niblings. It thrills me to let them experience it, and hopefully gives them the motivation to dream big.

A day before my trip, I learned my nephew Dan (18M) had fought with his mom. Dan’s a good kid, but my sister is toxic and verbally abusive. Anyway he left home and was staying with my uncle who lives in a tiny flat and whose bed is a thin mattress on the floor.

It didn’t feel right that I had this suite at a posh hotel while my nephew was sleeping on the floor. I messaged him when I landed, and suggested he come stay with me. He could take the bedroom and I'd happily take the sofa bed.

Then my niece, his twin Samantha (18F), messaged him asking where he was. I told Dan he could tell Sam he was with me (surprise!), and that she could even come over so we could have dinner together.

At dinner, Sam updated me on her life. She’s a full-time student with a job, paying for her own way through uni. But she’s mentally near breaking point and my sister is no help. Sam would often skip meals just so she had money to commute to work and school. At home, my sister is often yelling and screaming at someone, so it’s difficult to focus on school work or relax on a rare day off.

Sam's school happens to be nearby, so I said she could also stay at the suite. It's quiet and she could even use the business lounge to study in peace. She and Dan would share the King bed.

I scrapped my surprise idea and told my sister her kids were with me so she wouldn't worry.

**Now here's where I might be an AH.**

My oldest adult niece is Bea (22F). She lives with her husband (currently away for work) and their 4yo son. When she found out that Dan and Sam were staying in a suite in a nice hotel, with a buffet breakfast every morning, and dinner at classy restaurants, she got jealous and started saying things like "I see who uncle's favourite people are" and "nobody likes me since I had my baby."

I said she could come and share the king bed if Sam and Dan were willing (they were). But I honestly didn't want to cause Bea would bring her kid and I'm not keen on sharing my space with a toddler. Also I use the suite to work when the lounge is full or closed. I'd book them a separate room if she really wanted, but the hotel's packed. Anyway, I'd be expected to compensate for transportation, food, and entertainment for her and her kid. This isn't gonna hurt me financially but I don't want to set a precedent where I'm expected to pay for the entire family tree during visits.

Bea left the family group chat and unfriended me after she saw pics Sam shared on Facebook. I've tried to be understanding, but it feels ridiculously petty.

I never intended anyone to feel left out. I just wanted to help, but now there's conflict brewing between Bea and the twins. I don't know if I did the right thing, or if I'm an AH who could've handled this situation better.

Edit: typos and edited sentences for clarity