My inmate son didn't get proper med. treatment til 2 days after assault. Has lost vision in one eye. Can he sue?

It all depends on what actually caused the loss of vision. If the assault cost him his vision, there's no case. If there was a possibility of saving his vision with timely treatment, he can absolutely sue the prison for negligence, and possibly the doctors for medical malpractice.  It all depends upon whether a doctor who reviews his records can testify with a reasonable degree of medical certainty that but for the delay, your son would not have lost his vision. If it's a case of improper treatment once he was seen by a doctor, it's the same standard to prove medical malpractice. But you MUST serve a notice of claim on the county or state (depending on which prison) within 90 days of the day of the injury = before December 4th- in order to preserve his claim.