How did Lobotomization victims survive? Physically speaking.
Especially when it comes to Freeman's horrific "At Home" procedures. From what I have heard, he was not a trained surgeon and generally did not work within proper operating rooms. His methods were so crude and so brutal that even many proponents of Lobotomy spoke out against him.
He devastated his victims brains with an icepick. This left most of them husks of their former selves. Not all of them survived, his mortality rate (he should be considered a serial killer, really) was incredibly high, but some seem to have lived for many years - even decades. I'm honestly astounded more didn't die quickly from medical complications. Even setting aside the trauma and risk of hemorrhaging, surely infection would be a major concern? It doesn't sound like he was particularly hygienic. And he certainly wasn't careful.