Waist-high Compression stockings, but daughter has constant UTI/kidney infections

My D19 has POTS. Do they make ones without crotches or would it just make your blood pool there? Her doctor told her to wear waist-high compression stockings, not only leg ones. However, that the worst possible idea to me as she gets chronic UTIs, even doing everything “perfectly” to avoid them. We haven’t even thought about it as she has been in the middle of battling kidney infection resistant to a few antibiotics for a month that sent her to the ER twice. She never felt any improvement with leg-only ones. (Yes seeing urologist and probably nephrologist now.)

Her doctor said before considering prescribing meds she has to wear waist high compression stockings and drink more water than she is able to. She has a sensitive system and if she drinks a lot of water she gets nauseous and throws it up.

She naturally has low blood pressure (genetic like me and family are 90/60ish), so beta blockers are not the answer it’s her heart rate.

She has asked me to accompany her to doctor appointments. I’ll be at the next one and I’m also a disability rights/special ed advocate, so I can be assertive, but in polite and productive manner.