What now?! Is it time to ask that they not treat again?

So this is going to be too long, I'm sure, but please just bear with me, PLEASE. My Dad went into the VA hospital on January 28th of this year, for sepsis, he was finally discharged in June. After being diagnosed with depression, PTSD (Vietnam), Ischemic heart disease, as well as an enlarged prostate (non cancerous) that has caused him to be permanently catheterized. We found out after admittance in January that the sepsis was caused by kidney stones so large they actually cut off the urine flow & cut into the kidney wall & made his kidney swell up 2 times it's normal size. He had drains inserted, directly into his kidneys via his back...2 surgeries to remove the stones & remaining fluids & an additional 2 surgeries to remove the tubes.

In the meantime the moderate confusion he was experiencing before the admittance has turned into full blown dementia. He also had a triple bypass surgery due to the Ischemic HD. During the 6 months in the hospital we have done nothing but fight UTI's & or Urosepsis. He actually has E. Coli constantly in his kidneys & or urethea. He's so weak that he cannot even begin to walk or do the PT required to get "well". For all intents and purposes he has not walked since January 28th. He literally just has come home (today in fact) from a second stint in a regular hospital, where he was diagnosed with Failure to Thrive. He requested Hospice himself, in a very rare & lucid moment and was granted it due to his declining health as well as his most recent diagnosis. As I said before, we just got home today & he's already showing signs of Urosepsis again...this is about the 10th time we have treated it. So my question is....Is it time to ask that they not treat it again...he has said he doesn't want anymore treatments or hospitals. Would this even be legal to request no meds? We're just not sure what to do next?! And the suffering he's been through has us all completely overwhelmed, exhausted and heartbroken. Any thoughts?!