Feeling guilty about not wanting to help my brother

My brother texted me today and asked if I could give him a ride to and from an outpatient medical procedure he has scheduled for the end of next week. Apparently his other options for transport fell through, hence the somewhat late notice. I'm going to help him if my boss is OK with me taking the day off, but I'm feeling guilty about how much I don't want to.

I love my brother. We're the only siblings, dad's gone, mom's an addict who's been out of our lives for years, and our nearest relatives are hours away in other states. He also helped me with a similar situation a couple years ago. Despite that, I can't help but think about how it will be a 200mi round trip drive and how I'll have to spend some of my precious PTO.

I like my job. It doesn't pay a lot and the benefits are pretty sparse, but it has been extremely good for my mental and physical health. Starting this job a year and a half ago was a major factor in me finally losing a significant amount of weight and breaking out of a decade-long severe mental health rut. I get very little PTO (about 1 week per year) and I hoard it like a dragon with their gold pile. It's also earned based on hours worked; slowly accumulated week by week, which makes it seem more rare and valuable. Am I planning on taking a vacation anytime soon? No. I can't afford it. So what I am saving my PTO for so obsessively? I couldn't say, but spending any of it feels painful at this point. I know it's not psychologically healthy, but that's where I am mentally atm. I absolutely can't afford to take the day off without using PTO either.

He earns more than me and has significantly better benefits, including a lot more PTO, so this isn't a subject I'm even remotely interested in broaching with him. He would feel guilty and I would feel like a broke loser. No one would win.

So...yeah. Just needed to get that off my chest around folks who understand.