While I'm not a medical peep, I do have personal experience with having sepsis, and it is the sickest I've ever been in my life. It came on very suddenly and I had no idea what hit me. A few things:
1) Put your health insurance's 24/7 triage nurse phone number in your phone. They saved my life. My heart was racing around 140bpm and I just thought I was having a major panic attack (I have a history of these). When the fever came on an hour or so later, that's when I called her and she told me very calmly, "Ma'am, you need to get to the ER within the next two hours." This was at midnight, so I woke up H, not knowing why I had to go to the ER, but only telling him he needed to get me there. The rest unfolded from there.
2) If he is not in the ICU, they think he is relatively stable. If he starts to crash, you will know because they will transfer him to the ICU. I was never in the ICU, and I kept telling myself that. From working in hospice, I knew that sepsis had a high mortality rate, and I was terrified. This is why I kept repeating to myself, "Number4, you're not in the ICU; Number4, you're not in the ICU." I was temporarily taken off of my blood pressure medication because sepsis can cause a decease in BP, so they don't want to push it down further with meds. I was in the hospital for five nights. Did I mention that it's the sickest I've ever felt?
3) Hopefully they will get a good culture that allows them to identify the specific bacteria - this will allow them to tailor the antibiotics to his needs. They put me on antibiotics in the ER after they got back the results of a CAT scan (I'd had a hysterectomy seven weeks earlier and they suspected an abscess, so they knew what area of my body was suspect), but a day or so later, when they fine tuned the bacteria causing me so much grief, they changed the antibiotic. I also had a minor procedure where they drained the abscess and put in a tube to allow for more draining. I got the tube out the day before I left the hospital.
4) I came home with a PICC line in place (that they also placed the day I came home), and a visiting nurse came to the house the next day to show me how to infuse my own antibiotics every day. I wasn't thrilled with that, but it was the only way to administer this particular antibiotic. She was very thorough, and had me walk through the process with her, the next day when she came back for a follow-up. I think she came every other day to collect blood samples, which I appreciated because I sure as hell didn't feel like getting off the couch and going to a lab somewhere. But if he comes home soon (and I'll address this further down), you will likely need to administer some sort of antibiotics.
5) While the aches/pains, rapid heart rate, chills, headache, etc., all began to subside within three days, I was still a hot mess. I had no energy whatsoever. Just sitting on the bench in our shower to wash my hair was exhausting. I think H had to wash my hair for me. I was in fairly good shape prior to the infection - but this took everything out of me... much more so than the hysterectomy itself. It was months before I felt like I had my energy back again. I had a couple of follow up visits with the infectious disease doctor that my D drove me to, as she came in town to help out while H worked. I remember when we pulled into the parking lot of the medical building, and I saw that I'd have to walk about 75 yards from the garage to the entrance of the building, I almost cried. I had to stop a couple of times to catch my breath.
6) In the end, I survived, but it created a lot of medical trauma for me - I just couldn't understand how I went from fine, about 6PM in the evening, when we took our dog for a 2-mile walk at the dog park (again, I was way above the healing curve from my surgery), to having a heart rate in the 140s and feeling like I wanted to die six hours later. When COVID hit, and there were endless stories of people in the hospital feeling the worse they'd ever felt, I was terrified of the possibility of ever feeling that sick again. I mean, now often do you hear about people staying five nights in the hospital now? Full knee replacements are now outpatient!!! So I knew I was sick. You might need to really consider letting him go to a skilled nursing facility when he's discharged from the hospital. He will need the kind of intensive observation that you might not be able to provide, given your H's sleep demands. The social worker at the hospital should already be talking to you about this, so you can start researching various facilities.
7) If he was in septic shock right now, he'd be in the ICU. But yea, they probably have an idea of which stage he's in. However, that can change quickly, so they will continue to monitor him very closely. Is he in a telemetry unit?
8) You shouldn't have to rely on your niece to teach you how to do a manual BP. Your H's health care team should make arrangements with a visiting nurse to teach you how. This is their job.
9) Did I mention it's the sickest I've ever felt?