Boil on my left butt cheek, need advice

I'm looking after this 89-year-old woman who lives in my neighborhood here in the States, and she doesn't have a pension or any health insurance, so I feel like it's basically my responsibility to help her out however I can. Luckily, she's actually in pretty good shape, so she hardly needs any meds—if she did, I'd probably go broke 🙂 mostly because—I can't really get a doctor to see her since she knows she isn't covered and she doesn't want me stuck with the massive bills 😠 she’s been dealing with a duodenal ulcer for years now; it was confirmed back in the late '70s at a clinic in Chicago (heaven knows how she even ended up there). She hasn't had any real treatment for it, though she’s spent years occasionally throwing up "bitter stuff," as she calls it, along with some lower back pain—which I assume is from the ulcer, though she insists it just happens when she catches a cold and vomits 🙄 anyway, since she's older, those symptoms happen more often and the vomiting just wears her out more. Pepto-Bismol helps, and after two or three bottles, she seems fine, but then the whole thing comes back every six months or so, usually during the fall or spring. This past spring was really bad because there wasn't anyone around to notice she needed the Pepto, and I honestly think she might have died from being so weak from vomiting if I hadn't stepped in in time. She was doing okay over the summer, so right before autumn hit, I gave her some Pepto to take once a day just to prevent another flare-up, but she wouldn't take it because she's trying to save the pills so I don't have to spend money 😠 and, well, of course, it started happening again—she was vomiting about ten days ago, and then again yesterday, once I found out why she wasn't taking the medicine.

since dealing with stuff like this totally drains me, I'm wondering if there's anything smart I can pick up at a local CVS or Walgreens? I was thinking—if it were some kind of cancer, she would've passed away a long time ago, and at her age without insurance, there isn't much medical help available anyway, because you eventually just die from something 🙂 on the other hand, if she has H. pylori, which could be why this ulcer keeps coming back, maybe there's some kind of treatment that could help, even if I'm just guessing. please, if anyone has advice, let me know what I should do, because I definitely need to do something 🙂 thanks in advance

Look, I get that you’ve got a good heart and you just want to look out for that elderly lady, but you really shouldn't be handing out medication without professional oversight.
You should probably walk your doctor through the whole situation and ask for their take on it, or honestly, just call Adult Protective Services since she's living alone and needs some actual support from the state.