Why didn't Kim just claim insanity for Jimmy?

Seems to me with jimmy having two personalities and plenty of witnesses that could attest to that. A insanity plea would seem like a easy go to in his defense.

Would of at least kept him out of prison and got him into a mental ward where Kim could maybe of set something up for him.

Jimmy was just as mentally ill as chuck was. The whole thing would of been pretty easy to establish jimmy made Saul up to cope with some sort of mental issue. Schizophrenia at its purest form.

Idk, just seems like they wrapped it up a little to much in a nice repent bow. Jimmy was a self saving rat. No amount of remorse would of let him sit in prison to die. His mental illness would of kicked in to keep him safe. Just like it had many many times before.