Interesting issue of sentencing him so long after the crime.
If he'd been caught at age 18, would he have potentially gotten the same period of parole inegibility, a shorter, or a longer, than he'll get now?
One thing about this crime
is that he brought the knife. So although he wasn't charged with 1st degree murder, it has that flavour. I think that would probably make the parole ineligibility longer than the standard 10 years.
Then, the lack of admission of guilt in spite of the overwhelming evidence against, and therefore of remorse, even after all this time and the chance to reflect and become more mature, seems to me that should almost count to lengthen parole ineligility (not sure whether that's legal principal, though).
Certainly, he won't be released on parole until he changes his tune, admits he was 100% guilty, is very remorseful, etc. It not an automatic 3.5 years and he's back to his old life.