Post-conviction sentence reduction success is rare. Getting a sentence dropped altogether will never happen, especially when you see a sentence of 103 years... this judge must have been very angry to hand down that time to an eighteen year old.
Your friend's best chance is if the judge allowed for a possibility of parole in the Judgement and Commitment papers. If that is available, then he will need to work VERY hard with the staff at the prison to make certain that he is in compliance with all programming requirements and that he does not get any incidence reports.
https://www.inmateaid.com/ask-the-inmate/is-there-any-way-to-get-your-sentence-reduced-after-serving-15-years-of-a.amp#answer
Accepted Answer Date Created: January 16,2016