When I experienced this with my dad I found there was a difference in what the hospital told us would happen and what actually happened.
The last time he was discharged we were told he'd be referred to the specialist community diabetes team.
He died several weeks later of sepsis after yet another infection, they tried to say the high blood sugars were due to food despite nothing changing in his diet. For him high blood sugars were an indication of infection but noone would listen.
The only solace for me is that he's no longer weary and in pain.