I am so glad your sister is feeling better. Sepsis moves really fast! My sepsis also started in the kidneys. I was feeling bad, but still teaching at 2:00
I had a dr appt at 4:00. They were behind, and by 4:30 I was unconscious on the office floor. I was in icu for 3 days and 3 more in a regular room. When I went home I had oral antibiotics. I assume your sister has oral medication also. It's always important to take the full term of medication, but with sepsis its even more imperative to take the full course and to take them on time. The follow up after the meds course is also important as the sepsis can return quickly.
Fortunatly I didn't have a reoccurance, but have heard of people who relapsed quickly. Your sister is foryunate that yoou are there to help her.
Hope you and your sister are feeling better.