"Thy brat hath been cast out, like to itself,
No father owning it."
If we read 'left to itself' we might get better sense.
"But yet hear this; mistake me not. No! life—
I prize it not a straw.... But, for mine honour."
So we may best punctuate, with Hanmer. We might perhaps read 'For life,' as above.
"Which you knew great, and to the hazard boldly."
The 2nd folio reads 'certain hazard.'