This is a serious set of charges with a decent amount of illegal drugs. The sentencing guidelines are harsh. Is he being prosecuted by the sheriff's department or the FBI? We need to know if it is a state charge or a federal charge. Unfortunately, first-time offenders are not afforded much of a break and with mandatory minimum sentencing guidelines in place the sentence could be hefty.
Here is our best advice: Most private attorneys are not worth what you pay them unless they have a track record of actually trying criminal cases in open court in front of a jury. A trial lawyer, not a litigator. You have to have a really good talk with your brother (outside the ears of the phone system) at visitation and find out what his tolerance is for gut-wrenching months of legal bullshit. If at the end of the day, the evidence is overwhelming and he has no one to deflect these charges onto, then he will probably get the best result with a plea deal. If he has a solid story, bad set of circumstances, plausible deniability then you might want to get a trial lawyer. What you don't need is a lawyer to negotiate a plea deal. The public defender's office knows the prosecutors as well as anyone. Use them for free to find out what they have on him and what they are looking for.
If you determine that the case needs to go to trial, then you need to get a beast. Wyoming's best criminal trial lawyer was Gerry Spence (Spence Law Firm) who is 87 now, but surely a conversation with him would glean great advice or at least the name of a couple of bad asses who will fight like crazy.
98% of the attorneys out there will sell you on their background (was a former prosecutor, or a former FBI agent, knows every judge, etc etc) and will get you all excited that they will fight for your brother and win. They will coax out of all the money you have (like they are doing you a favor). You write the check, they cash it and that is the end of the game for them. There will be 4-6 months of cat and mouse, you being the cat and HIM being the mouse. Finally you pin him in the corner and he will say, "Wow, they have a mountain of evidence against your brother. Way more that we first thought. I have real doubts about winning this case. BUT, I don't want to convince you to plead guilty if you want to go to trial. If you plea, I can get you 6-10 years, if you lose you are looking at 20-25 years - what do you want to do?" If he said this before taking your six-figure check, would have written it? So, this is the dilemma. If your brother can see a way to win with the evidence against him, them go the Spence's firm and get a killer on your side. If not, you don't need to pay tens of thousands of dollars to plead guilty.
https://www.inmateaid.com/ask-the-inmate/my-brother-was-arrested-for-intent-to-deliver-possession-of-major-drugs-should-he-plea#answer