Please do not go any further into details of a pending criminal case. Any information posted on a public forum such as this could hurt the person you are trying to help.
If the case has been going on for a year, the young man unquestionably has been assigned an attorney. If you believe that a prosecutor would dismiss a murder charge because a codefendant, who has already pled guilty, has already stated on the record that the other person was not involved, get that thought out of your head. For most prosecutors, this is a trial issue. The young man is facing a choice of either taking a plea bargain, as the codefendant did, or taking the case to trial. If he takes the case to trial, the People will have to prove to a jury that he committed whatever crimes they are charging him with, and prove each beyond a reasonable doubt. If he is found guilty of murder, yes, he could well be facing the maximum sentence of 25 years to life.
The risk of trial is great. If he is innocent, however, he may want to take that risk.
A new attorney would likely not change the situation. As to finding an attorney to work pro bono: few private attorneys would take on, for free, a murder case that may be going to trial. Few can afford to do so. A murder case is very serious, and requires a lot of time. In the rare case that is daily front page news, sometimes a publicity seeking private attorney might take such a case on for, essentially, advertising value, to get his name in the news. Would you really want that?
Your young man has a heavy decision to make. He should discuss this with his attorney.
DISCLAIMER: This answer to a short simplified question is provided solely for general informational purposes only and is not intended to provide the specific legal advice you might need to decide your future actions. It is intended to provide you, and others with similar issues, a general, common-sense idea of the situation. Please consult with a local attorney to evaluate your particular case in the depth it deserves. This answer does not constitute legal advice, create an attorney-client relationship, or constitute attorney advertising.